Updated on 2022/06/29

写真a

 
SEKINE, Yasushi
 
Affiliation
Faculty of Science and Engineering, School of Advanced Science and Engineering
Job title
Professor

Concurrent Post

  • Faculty of Science and Engineering   Graduate School of Advanced Science and Engineering

Research Institute

  • 2020
    -
    2022

    理工学術院総合研究所   兼任研究員

Education

  •  
    -
    1998

    The University of Tokyo   Graduate School, Division of Engineering  

  •  
    -
    1993

    The University of Tokyo   Faculty of Engineering   Department of Applied Chemistry  

Degree

  • 博士(工学)・東大

Research Experience

  • 2018.04
    -
    Now

    JST   さきがけ総括

  • 2012
    -
    Now

    Waseda University   Faculty of Science and Engineering

  • 2011
    -
    Now

    Japan Science and Technology Agency

  • 2007
    -
    2012

    Waseda University   Faculty of Science and Engineering

  • 2006
    -
    2007

    Waseda University   Faculty of Science and Engineering

  • 2003
    -
    2006

    Waseda University   Institute for Nanoscience and Nanotechnology

  • 2001
    -
    2003

    Waseda University   School of Science and Engineering

  • 1998
    -
    2001

    The University of Tokyo   The Graduate School of Engineering, Department of Applied Chemistry

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Professional Memberships

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    水素エネルギー協会

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    理論化学会

  •  
     
     

    日本化学連合

  •  
     
     

    日本化学会

  •  
     
     

    American Chemical Society

  •  
     
     

    石油学会

  •  
     
     

    触媒学会

  •  
     
     

    静電気学会

  •  
     
     

    固体イオニクス学会

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    日本鉄鋼協会

  •  
     
     

    プラスチックリサイクル化学研究会

  •  
     
     

    電気化学会

  •  
     
     

    日本エネルギー学会

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Research Areas

  • Energy chemistry

  • Catalyst and resource chemical process

Research Interests

  • 触媒・化学プロセス、触媒化学、資源エネルギー化学

Papers

  • Elucidation of the reaction mechanism on dry reforming of methane in an electric field by in situ DRIFTs

    Naoya Nakano, Maki Torimoto, Hiroshi Sampei, Reiji Yamashita, Ryota Yamano, Koki Saegusa, Ayaka Motomura, Kaho Nagakawa, Hideaki Tsuneki, Shuhei Ogo, Yasushi Sekine

    RSC Advances   12 ( 15 ) 9036 - 9043  2022.03

     View Summary

    With increasing expectations for carbon neutrality, dry reforming is anticipated for direct conversion of methane and carbon dioxide: the main components of biogas. We have found that dry reforming of methane in an electric field using a Pt/CeO2 catalyst proceeds with sufficient rapidity even at a low temperature of about 473 K. The effect of the electric field (EF) on dry reforming was investigated using kinetic analysis, in situ DRIFTs, XPS, and DFT calculation. In situ DRIFTs and XPS measurements indicated that the amount of carbonate, which is an adsorbed species of CO2, increased with the application of EF. XPS measurements also confirmed the reduction of CeO2 by the reaction of surface oxygen and CH4. The reaction between CH4 molecules and surface oxygen was promoted at the interface between Pt and CeO2

    DOI

  • Elucidation of catalytic NO<inf>x</inf> reduction mechanism in an electric field at low temperatures

    Ayaka Shigemoto, Takuma Higo, Yuki Narita, Seiji Yamazoe, Toru Uenishi, Yasushi Sekine

    Catalysis Science and Technology    2022

     View Summary

    As automobiles increasingly become electrically driven and as more engines and motors are used together, the exhaust temperatures of internal combustion engines are decreasing. Further improvement of exhaust gas purification catalyst performance is necessary. To purify nitrogen oxides, unburned hydrocarbons, and carbon monoxide simultaneously at low temperatures, electrothermal heating and plasma catalysis have been proposed, but these methods require high power consumption. Results of this study indicate that a direct current electric field applied to a Pd-supported catalyst shows high purification rates even at temperatures lower than 473 K under TWC conditions (NO-CO-C3H6-O2-H2O). For clarifying the reaction mechanism in this process, the adsorption of reactants was evaluated using in situ DRIFTS measurements in an electric field. Factors that improve the activity at low temperatures in the electric field were clarified.

    DOI

  • Efficient CO<inf>2</inf> conversion to CO using chemical looping over Co-In oxide

    Jun Ichiro Makiura, Sota Kakihara, Takuma Higo, Naoki Ito, Yuichiro Hirano, Yasushi Sekine

    Chemical Communications    2022

     View Summary

    CO2 conversion to CO by reverse water-gas shift using chemical looping (RWGS-CL) can be conducted at lower temperatures (ca. 723-823 K) than the conventional catalytic RWGS (>973 K), and has been attracting attention as an efficient process for CO production from CO2. In this study, Co-In2O3 was developed as an oxygen storage material (OSM) that can realize an efficient RWGS-CL process. Co-In2O3 showed a high CO2 splitting rate in the mid-temperature range (723-823 K) compared with previously reported materials and had high durability through redox cycles. Importantly, the maximum CO2 conversion in the CO2 splitting step (ca. 80%) was much higher than the equilibrium conversion of catalytic RWGS in the mid-temperature range, indicating that Co-In2O3 is a suitable OSM for the RWGS-CL process.

    DOI PubMed

  • Recent Trends on the Dehydrogenation Catalysis of Liquid Organic Hydrogen Carrier (LOHC): A Review

    Yasushi Sekine, Takuma Higo

    Topics in Catalysis   64 ( 7-8 ) 470 - 480  2021.07

     View Summary

    Considering the expansion of the use of renewable energy in the future, the technology to store and transport hydrogen will be important. Hydrogen is gaseous at an ambient condition, diffuses easily, and its energy density is low. So liquid organic hydrogen carriers (LOHCs) have been proposed as a way to store hydrogen in high density. LOHC can store, transport, and use hydrogen at high density by hydrogenation and dehydrogenation cycles. In this review, we will focus on typical LOHCs, methylcyclohexane (MCH), 18H-dibenzyltoluene (DBT), and 12H-N-ethylcarbazole (NECZ), and summarize recent developments in dehydrogenation catalytic processes, which are key in this cycle.

    DOI

  • Electrical promotion-assisted automotive exhaust catalyst: highly active and selective NO reduction to N<inf>2</inf>at low-temperatures

    Yuki Omori, Ayaka Shigemoto, Kohei Sugihara, Takuma Higo, Toru Uenishi, Yasushi Sekine

    Catalysis Science and Technology   11 ( 12 ) 4008 - 4011  2021.06

     View Summary

    A Pd catalyst (Pd/Ce0.7Zr0.3O2) in an electric field exhibits extremely high three-way catalytic activity (TWC: NO-C3H6-CO-O2-H2O). By applying an electric field to the semiconductor catalyst, low-temperature operation of TWC can be achieved even at 473 K by virtue of the activated surface-lattice oxygen.

    DOI

  • Co-CeO<inf>2</inf>Interaction Induces the Mars-van Krevelen Mechanism in Dehydrogenation of Ethane

    Yukiko Hosono, Hikaru Saito, Takuma Higo, Kosuke Watanabe, Kazuharu Ito, Hideaki Tsuneki, Shun Maeda, Kunihide Hashimoto, Yasushi Sekine

    Journal of Physical Chemistry C   125 ( 21 ) 11411 - 11418  2021.06

     View Summary

    Introducing a catalyst for dehydrogenation of ethane (EDH) for steam cracking represents a promising solution with high feasibility to realize efficient ethylene production. We investigated EDH over transition-metal-doped CeO2 catalysts at 873 K in the presence of steam. Ce0.8Co0.2O2 exhibited high EDH activity and selectivity to ethylene (ca. 95%). In the absence of H2O, the catalytic activity dropped rapidly, indicating the promotive effect of H2O on ethylene formation. Catalytic experiments with water isotopes (D2O and H218O) demonstrated that EDH over Ce0.8Co0.2O2 proceeds through the Mars-van Krevelen (MvK) mechanism in which the reactive lattice oxygen in Ce0.8Co0.2O2 contributes to EDH. The consumed lattice oxygen was subsequently regenerated with H2O. X-ray diffraction and in situ X-ray absorption fine structure spectroscopy revealed that cobalt species were mainly present as CoO under EDH conditions and that redox between Co2+ and Co0 proceeded concomitantly with EDH. In contrast with Ce0.8Co0.2O2, no contribution of the lattice oxygen of CoO to EDH was verified in the case of CoO supported on α-Al2O3, which exhibited lower activity than Ce0.8Co0.2O2. Therefore, Co-CeO2 interactions are expected to play a crucially important role in controlling the characteristics of the reactive lattice oxygen suitable for EDH via the MvK mechanism.

    DOI

  • Different mechanisms of ethane aromatization over Mo/ZSM-5 and Ga/ZSM-5 catalysts

    Evgeny A. Uslamin, Hikaru Saito, Yasushi Sekine, Emiel J.M. Hensen, Nikolay Kosinov

    Catalysis Today   369   184 - 192  2021.06  [Refereed]

     View Summary

    Aromatization of light hydrocarbons can contribute to a secure supply of aromatics for the chemical industry. In this work, we investigate the influence of modification of zeolite ZSM-5 with Ga and Mo on the reaction mechanism underlying the activation and aromatization of ethane. Well-defined Mo/ZSM-5 and Ga/ZSM-5 zeolites efficiently promote ethane aromatization to benzene-toluene-xylene mixtures. Both catalysts suffer from coke formation, which leads to rapid deactivation. From catalytic tests, temperature-programmed surface reaction and pulsed reaction experiments, we infer that ethane conversion on Ga/ZSM-5 follows a conventional sequential dehydrogenation-oligomerization-aromatization mechanism, while the reaction over Mo/ZSM-5 involves reactive surface carbon (hydrocarbon pool) species.

    DOI

  • Synthesis of FAU-Zeolite Membrane by a Secondary Growth Method: Influence of Seeding on Membrane Growth and Its Performance in the Dehydration of Isopropyl Alcohol-Water Mixture

    Masahiko Matsukata, Yasushi Sekine, Eiichi Kikuchi, Motomu Sakai, Bharathi Subramanian, Makoto Toyoda, Taisuke Furuhata

    ACS Omega   6 ( 14 ) 9834 - 9842  2021.04

     View Summary

    Y-type zeolite membranes were prepared on a porous tubular α-alumina support by a secondary growth process. Various experimental conditions such as seed size, pH of seed solution, and degassing of support were examined for understanding their influence on the membrane deposition process. The experimental results showed that the potential of alumina support surface and the USY seed slurry plays a significant role in controlling the electrostatic interaction between seed particles and support surface and also the aggregation of USY seed particles in the slurry. In addition, we also noted the significance of the capillary forces working at the three-phase interface on the support surface and is a key factor that governs the seeding behavior onto the tubular support surface. Optimization of these parameters resulted in crack-free compact membranes that were able to effectively separate a mixture of isopropyl alcohol and water in a vapor-phase separation process.

    DOI

  • Manipulation of CO adsorption over Me<inf>1</inf>/CeO<inf>2</inf> by heterocation doping: Key roles of single-atom adsorption energy

    Kota Murakami, Yuta Mizutani, Hiroshi Sampei, Atsushi Ishikawa, Yasushi Sekine

    Journal of Chemical Physics   154 ( 16 )  2021.04

     View Summary

    The performance of metal atoms chemically bonded to oxide supports cannot be explained solely by the intrinsic properties of the metals such as the d-band center. Herein, we present an in-depth study of the correlation between metal-oxide interactions and the properties of the supported metal using CO adsorption on Me1 (Fe1, Co1, and Ni1) loaded over CeO2 (111) doped with divalent (Ca, Sr, and Ba), trivalent (Al, Ga, Sc, Y, and La), and quadrivalent (Hf and Zr) heterocations. CO adsorption over Me1 is strongly dependent on the binding energies of Me1. Two factors led to this trend. First, the extent of the Me1-surface oxygen (Me1-O) bond relaxation during CO adsorption played a key role. Second, the d-band center shifted drastically because of charge transfer to the oxides. The shift is related to the oxophilicity of metals. Adsorption energies of Me1 over oxides include the contributions of the factors described above. Therefore, we can predict the activities of Me1 using the strength of anchoring by oxide supports. Results show that smaller ionic radii of the doped heterocations were associated with more tightly bound Me1. This finding sheds light on the possibility of heterocation-doping manipulating the reactivity of the Me1 catalyst based on theoretical predictions.

    DOI PubMed

  • Theoretical prediction by DFT and experimental observation of heterocation-doping effects on hydrogen adsorption and migration over the CeO<inf>2</inf>(111) surface

    Kota Murakami, Yuta Mizutani, Hiroshi Sampei, Atsushi Ishikawa, Yuta Tanaka, Sasuga Hayashi, Sae Doi, Takuma Higo, Hideaki Tsuneki, Hiromi Nakai, Yasushi Sekine

    Physical Chemistry Chemical Physics   23 ( 8 ) 4509 - 4516  2021.02

     View Summary

    Hydrogen (H) atom adsorption and migration over the CeO2-based materials surface are of great importance because of its wide applications to catalytic reactions and electrochemical devices. Therefore, comprehensive knowledge for controlling the H atom adsorption and migration over CeO2-based materials is crucially important. For controlling H atom adsorption and migration, we investigated irreducible divalent, trivalent, and quadrivalent heterocation-doping effects on H atom adsorption and migration over the CeO2(111) surface using density functional theory (DFT) calculations. Results revealed that the electron-deficient lattice oxygen (Olat) and the flexible CeO2matrix played key roles in strong adsorption of H atoms. Heterocations with smaller valence and smaller ionic radius induced the electron-deficient Olat. In addition, smaller cation doping enhanced the CeO2matrix flexibility. Moreover, we confirmed the influence of H atom adsorption controlled by doping on surface proton migration (i.e.surface protonics) and catalytic reaction involving surface protonics (NH3synthesis in an electric field). Results confirmed clear correlation between H atom adsorption energy and surface protonics.

    DOI PubMed

  • Effects of A-site composition of perovskite (Sr<inf>1−x</inf>Ba<inf>x</inf>ZrO<inf>3</inf>) oxides on H atom adsorption, migration, and reaction

    Yuta Tanaka, Kota Murakami, Sae Doi, Kazuharu Ito, Koki Saegusa, Yuta Mizutani, Sasuga Hayashi, Takuma Higo, Hideaki Tsuneki, Hiromi Nakai, Yasushi Sekine

    RSC Advances   11 ( 13 ) 7621 - 7626  2021.02

     View Summary

    Hydrogen (H) atomic migration over a metal oxide is an important surface process in various catalytic reactions. Control of the interaction between H atoms and the oxide surfaces is therefore important for better catalytic performance. For this investigation, we evaluated the adsorption energies of the H atoms over perovskite-type oxides (Sr1−xBaxZrO3; 0.00 ≤x≤ 0.50) using DFT (Density Functional Theory) calculations, then clarified the effects of cation-substitution in the A-site of perovskite oxides on H atom adsorption, migration, and reaction. Results indicated local distortion at the oxide surface as a key factor governing H atom adsorption. Subtle Ba2+substitution for Sr2+sites provoked local distortion at the Sr1−xBaxZrO3oxide surface, which led to a decrement in the H atom adsorption energy. Furthermore, the effect of Sr2+/Ba2+ratio on the H atoms' reactivities was examined experimentally using a catalytic reaction, which was promoted by activated surface H atoms. Results show that the surface H atoms activated by the substitution of Sr2+sites with a small amount of Ba2+(x= 0.125) contributed to enhancement of ammonia synthesis rate in an electric field, which showed good agreement with predictions made using DFT calculations.

    DOI

  • Fast oxygen ion migration in Cu-In-oxide bulk and its utilization for effective CO<inf>2</inf>conversion at lower temperature

    Jun Ichiro Makiura, Takuma Higo, Yutaro Kurosawa, Kota Murakami, Shuhei Ogo, Hideaki Tsuneki, Yasushi Hashimoto, Yasushi Sato, Yasushi Sekine

    Chemical Science   12 ( 6 ) 2108 - 2113  2021.02

     View Summary

    Efficient activation of CO2at low temperature was achieved by reverse water-gas shiftviachemical looping (RWGS-CL) by virtue of fast oxygen ion migration in a Cu-In structured oxide, even at lower temperatures. Results show that a novel Cu-In2O3structured oxide can show a remarkably higher CO2splitting rate than ever reported. Various analyses revealed that RWGS-CL on Cu-In2O3is derived from redox between Cu-In2O3and Cu-In alloy. Key factors for high CO2splitting rate were fast migration of oxide ions in the alloy and the preferential oxidation of the interface of alloy-In2O3in the bulk of the particles. The findings reported herein can open up new avenues to achieve effective CO2conversion at lower temperatures.

    DOI

  • Reaction mechanism of low-temperature catalysis by surface protonics in an electric field

    Yasushi Sekine, Ryo Manabe

    Faraday Discussions   229   341 - 358  2021.02

     View Summary

    The process of combining heterogeneous catalysts and direct current (DC) electric fields can achieve high catalytic activities, even under mild conditions (<500 K) with relatively low electrical energy consumption. Hydrogen production by steam reforming of methane, aromatics and alcohol, dehydrogenation of methylcyclohexane, dry reforming of methane, and ammonia synthesis are known to proceed at low temperatures in an electric field. In situ/operando analyses are conducted using IR, Raman, X-ray absorption fine structure, electrochemical impedance spectroscopy, and isotopic kinetic analyses to elucidate the reaction mechanism for these reactions at low temperatures. The results show that surface proton hopping by a DC electric field, called surface protonics, is important for these reactions at low temperatures because of the higher surface adsorbate concentrations at lower temperatures. This journal is

    DOI PubMed

  • Three-Way Catalytic Reaction in an Electric Field for Exhaust Emission Control Application

    Toru Uenishi, Ayaka Shigemoto, Yuki Omori, Takuma Higo, Shuhei Ogo, Yasushi Sekine

    SAE Technical Papers   ( 2021 )  2021

     View Summary

    To prevent global warming, further reductions in carbon dioxide are required. It is therefore important to promote the spread of electric vehicles powered by internal combustion engines and electric vehicles without internal combustion engines. As a result, emissions from hybrid electric vehicles equipped with internal combustion engines should be further reduced. Interest in catalytic reactions in an electric field with a higher catalytic activity compared to conventional catalysts has increased because this technology consumes less energy than other electrical heating devices. This study was therefore undertaken to apply a catalytic reaction in an electric field to an exhaust emission control. First, the original experimental equipment was built with a high voltage system used to conduct catalytic activity tests. Second, experiments with palladium cerium-zirconium oxide support catalysts showed that a three-way catalytic activity in an electric field could be found. at lower exhaust temperatures than conventional catalysts. Then it became clear that catalytic compositions that include semiconductor properties are a key for researching and developing this technology. In addition, applied electrical current control has been shown to be another focus of research and development. Finally, experimental results with several reducing species demonstrate that the electron-promoted surface proton and lattice oxygen greatly contributed to catalytic activity in an electric field.

    DOI

  • Recent progress in use and observation of surface hydrogen migration over metal oxides

    Kota Murakami, Yasushi Sekine

    Physical Chemistry Chemical Physics   22 ( 40 ) 22852 - 22863  2020.10

     View Summary

    © 2020 the Owner Societies. Hydrogen migration over a metal oxide surface is an extremely important factor governing the activity and selectivity of various heterogeneous catalytic reactions. Passive migration of hydrogen governed by a concentration gradient is called hydrogen spillover, which has been investigated broadly for a long time. Recently, well-fabricated samples and state-of-the-art measurement techniques such as operando spectroscopy and electrochemical analysis have been developed, yielding findings that have elucidated the migration mechanism and novel utilisation of hydrogen spillover. Furthermore, great attention has been devoted to surface protonics, which is hydrogen migration activated by an electric field, as applicable for novel low-temperature catalysis. This article presents an overview of catalysis related to hydrogen hopping, sophisticated analysis techniques for hydrogen migration, and low-temperature catalysis using surface protonics.

    DOI PubMed

  • Promotive effect of H<inf>2</inf>O on low-temperature NO reduction by CO over Pd/La<inf>0.9</inf>Ba<inf>0.1</inf>AlO<inf>3-</inf><inf>δ</inf>

    Takuma Higo, Yuki Omori, Ayaka Shigemoto, Kohei Ueno, Shuhei Ogo, Yasushi Sekine

    Catalysis Today   352   192 - 197  2020.08  [Refereed]

     View Summary

    © 2019 Elsevier B.V. For future removal of NOx by catalysts, low-temperature NO reduction is desired. Results confirmed that a drastic improvement of catalytic activity by H2O on NO–CO–O2 reaction over Pd/La0.9Ba0.1AlO3-δ catalyst at the low temperature of 473 K or below. In a humidified condition, NO reaction with CO on Pd/La0.9Ba0.1AlO3-δ proceeded without being affected by competitive adsorption of NO and CO, whereas that on Pd/Al2O3 was inhibited by strong adsorption of CO on a Pd surface. From in-situ DRIFTS measurements, results showed that nitrite species on the support react with CO adsorbed onto Pd at the periphery of Pd particles and that carbonate species accumulated on Pd/La0.9Ba0.1AlO3-δ are removed rapidly in a humidified condition. Although NO reduction proceeds dominantly on the Pd surface in a dry condition, supplied steam promotes desorption of the surface carbonate to advance the reaction of nitrite with CO for de-NOx in a humidified condition. This mechanism occurs specifically on Pd/La0.9Ba0.1AlO3-δ by virtue of the lattice oxygen and oxygen vacancy on La0.9Ba0.1AlO3-δ.

    DOI

  • Support effects on catalysis of low temperature methane steam reforming

    Maki Torimoto, Shuhei Ogo, Yudai Hisai, Naoya Nakano, Ayako Takahashi, Quanbao Ma, Jeong Gil Seo, Hideaki Tsuneki, Truls Norby, Yasushi Sekine

    RSC Advances   10 ( 44 ) 26418 - 26424  2020.07  [Refereed]

     View Summary

    © 2020 The Royal Society of Chemistry. Low temperature (<500 K) methane steam reforming in an electric field was investigated over various catalysts. To elucidate the factors governing catalytic activity, activity tests and various characterization methods were conducted over various oxides including CeO2, Nb2O5, and Ta2O5 as supports. Activities of Pd catalysts loaded on these oxides showed the order of CeO2 > Nb2O5 > Ta2O5. Surface proton conductivity has a key role for the activation of methane in an electric field. Proton hopping ability on the oxide surface was estimated using electrochemical impedance measurements. Proton transport ability on the oxide surface at 473 K was in the order of CeO2 > Nb2O5 > Ta2O5. The OH group amounts on the oxide surface were evaluated by measuring pyridine adsorption with and without H2O pretreatment. Results indicate that the surface OH group concentrations on the oxide surface were in the order of CeO2 > Nb2O5 > Ta2O5. These results demonstrate that the surface concentrations of OH groups are related to the proton hopping ability on the oxide surface. The concentrations reflect the catalytic activity of low-temperature methane steam reforming in the electric field.

    DOI

  • The important role of N<inf>2</inf>H formation energy for low-temperature ammonia synthesis in an electric field

    Kota Murakami, Yuta Tanaka, Ryuya Sakai, Kenta Toko, Kazuharu Ito, Atsushi Ishikawa, Takuma Higo, Tomohiro Yabe, Shuhei Ogo, Masatoshi Ikeda, Hideaki Tsuneki, Hiromi Nakai, Yasushi Sekine

    Catalysis Today   351   119 - 124  2020.07  [Refereed]

     View Summary

    © 2018 Elsevier B.V. Development of a highly efficient ammonia synthesis process is desirable for achieving a sustainable society. Regarding conventional heterogeneous catalysts, Ru-supported catalyst exhibits higher turn-over frequency (TOF) than Fe-supported or Ni-supported catalysts. However, we found that Fe-supported and Ni-supported catalysts show higher TOF than Ru-supported catalyst in an electric field at the low temperature of 373 K. Density functional theory (DFT) calculations revealed that N2 dissociation through the “associative mechanism” plays a key role in the electric field. The ammonia synthesis activity in the electric field is determined by the N2H formation energy at the metal-support interface.

    DOI

  • Catalytic conversion of ethane to valuable products through non-oxidative dehydrogenation and dehydroaromatization

    Hikaru Saito, Yasushi Sekine

    RSC Advances   10 ( 36 ) 21427 - 21453  2020.06  [Refereed]

     View Summary

    © The Royal Society of Chemistry 2020. Chemical utilization of ethane to produce valuable chemicals has become especially attractive since the expanded utilization of shale gas in the United States and associated petroleum gas in the Middle East. Catalytic conversion to ethylene and aromatic hydrocarbons through non-oxidative dehydrogenation and dehydroaromatization of ethane (EDH and EDA) are potentially beneficial technologies because of their high selectivity to products. The former represents an attractive alternative to conventional thermal cracking of ethane. The latter can produce valuable aromatic hydrocarbons from a cheap feedstock. Nevertheless, further progress in catalytic science and technology is indispensable to implement these processes beneficially. This review summarizes progress that has been achieved with non-oxidative EDH and EDA in terms of the nature of active sites and reaction mechanisms. Briefly, platinum-, chromium- and gallium-based catalysts have been introduced mainly for EDH, including effects of carbon dioxide co-feeding. Efforts to use EDA have emphasized zinc-modified MFI zeolite catalysts. Finally, some avenues for development of catalytic science and technology for ethane conversion are summarized.

    DOI

  • Catalytic Dehydrogenation of Ethane over Doped Perovskite via the Mars-van Krevelen Mechanism

    Kenta Toko, Kazuharu Ito, Hikaru Saito, Yukiko Hosono, Kota Murakami, Satoshi Misaki, Takuma Higo, Shuhei Ogo, Hideaki Tsuneki, Shun Maeda, Kunihide Hashimoto, Hiromi Nakai, Yasushi Sekine

    Journal of Physical Chemistry C   124 ( 19 ) 10462 - 10469  2020.05  [Refereed]

     View Summary

    Copyright © 2020 American Chemical Society. For effective utilization of ethane in natural gas, catalytic dehydrogenation of ethane is a promising option that offers better efficiency than ethane cracking to produce ethylene, the most important fundamental chemical. Recently, it was reported that catalytic dehydrogenation of ethane proceeds effectively on doped perovskite oxide via the Mars-van Krevelen (MvK) mechanism. For this work, the reaction mechanism was investigated using density functional theory calculations. Results demonstrated that ethane activation over perovskite (La1-xBaxMnO3-δ) proceeds at the surface lattice oxygen coordinated with Ba, resulting in a low energy barrier of the C-H bond activation. Based on Bader charge analysis, the electron-deficient surface lattice oxygen, which is favorable for hydrogen abstraction from light alkanes, forms around Ba. In addition, the electronic charges of the surface lattice oxygen are important for H2 desorption. The electronic charge depends on hydrogen coverage: electron-rich surface lattice oxygen, which is favorable for H2 desorption, forms at high hydrogen coverage. Therefore, a part of the surface lattice oxygens of perovskite would be covered with hydrogen atoms under the reaction atmosphere, leading to effective H2 desorption and the proceeding catalytic cycle via the MvK mechanism.

    DOI

  • Aromatization of ethylene over zeolite-based catalysts

    Evgeny A. Uslamin, Hikaru Saito, Nikolay Kosinov, Evgeny Pidko, Yasushi Sekine, Emiel J.M. Hensen

    Catalysis Science and Technology   10 ( 9 ) 2774 - 2785  2020.05  [Refereed]

     View Summary

    This journal is © The Royal Society of Chemistry. Light aromatic compounds (BTX: benzene, toluene and xylenes) represent an important class of building blocks in the chemical industry. Currently, light aromatics are obtained exclusively from fossil feedstock, whose utilization is associated with serious environmental concerns. Developing new routes for a more sustainable BTX production is, therefore, of high importance. In this work, aromatization of ethylene over well-defined metal-modified HZSM-5 zeolite catalysts is examined. The results show that modification of zeolite with gallium, zinc and silver leads to a significant increase in aromatics production. Metal species are responsible for catalysing dehydrogenation pathways with Ga being the most efficient for BTX production. Increasing temperature and ethylene partial pressure facilitate ethylene aromatization. Employing a combination of isotope labelling with a thorough characterization of zeolite-entrapped species by means of IR and MAS NMR spectroscopy provides evidence for the involvement of intra-zeolite aromatic hydrocarbon species in the catalytic cycle.

    DOI

  • Effects of metal cation doping in CeO<inf>2</inf> support on catalytic methane steam reforming at low temperature in an electric field

    Ayako Takahashi, Reona Inagaki, Maki Torimoto, Yudai Hisai, Taku Matsuda, Quanbao Ma, Jeong Gil Seo, Takuma Higo, Hideaki Tsuneki, Shuhei Ogo, Truls Norby, Yasushi Sekine

    RSC Advances   10 ( 25 ) 14487 - 14492  2020.04  [Refereed]

     View Summary

    This journal is © 2020 The Royal Society of Chemistry. Catalytic methane steam reforming was conducted at low temperature using a Pd catalyst supported on Ce1-xMxO2 (x = 0 or 0.1, M = Ca, Ba, La, Y or Al) oxides with or without an electric field (EF). The effects of the catalyst support on catalytic activity and surface proton hopping were investigated. Results show that Pd/Al-CeO2 (Pd/Ce0.9Al0.1O2) showed higher activity than Pd/CeO2 with EF, although their activity was identical without EF. Thermogravimetry revealed a larger amount of H2O adsorbed onto Pd/Al-CeO2 than onto Pd/CeO2, so Al doping to CeO2 contributes to greater H2O adsorption. Furthermore, electrochemical conduction measurements of Pd/Al-CeO2 revealed a larger contribution of surface proton hopping than that for Pd/CeO2. This promotes the surface proton conductivity and catalytic activity during EF application.

    DOI

  • Agglomeration Suppression of a Fe-Supported Catalyst and its Utilization for Low-Temperature Ammonia Synthesis in an Electric Field

    Ryuya Sakai, Kota Murakami, Yuta Mizutani, Yuta Tanaka, Sasuga Hayashi, Atsushi Ishikawa, Takuma Higo, Shuhei Ogo, Hideaki Tsuneki, Hiromi Nakai, Yasushi Sekine

    ACS Omega   5 ( 12 ) 6846 - 6851  2020.03  [Refereed]

     View Summary

    © 2020 American Chemical Society. Fe-supported heterogeneous catalysts are used for various reactions, including ammonia synthesis, Fischer-Tropsch synthesis, and exhaust gas cleaning. For the practical use of Fe-supported catalysts, suppression of Fe particle agglomeration is the most important issue to be resolved. As described herein, we found that Al doping in an oxide support suppresses agglomeration of the supported Fe particle. Experimental and computational studies revealed two tradeoff Al doping effects: the Fe particle size decreased and remained without agglomeration by virtue of the anchoring effect of doped Al. Also, some Fe atoms anchored by Al cannot function as an active site because of bonding with oxygen atoms. Using an appropriate amount of Al doping is effective for increasing the number of active Fe sites and catalytic activity. This optimized catalyst showed high practical activity and stability for low-temperature ammonia synthesis in an electric field. The optimized catalyst of 12.5 wt % Fe/Ce0.4Al0.1Zr0.5O2-δ showed the highest ammonia synthesis rate (2.3 mmol g-1 h-1) achieved to date under mild conditions (464 K, 0.9 MPa) in an electric field among the Fe catalysts reported.

    DOI

  • Key factor for the anti-Arrhenius low-temperature heterogeneous catalysis induced by H+ migration: H+ coverage over support

    Kota Murakami, Yuta Tanaka, Ryuya Sakai, Yudai Hisai, Sasuga Hayashi, Yuta Mizutani, Takuma Higo, Shuhei Ogo, Jeong Gil Seo, Hideaki Tsuneki, Yasushi Sekine

    Chemical Communications   56 ( 23 ) 3365 - 3368  2020.03  [Refereed]

     View Summary

    © 2020 The Royal Society of Chemistry. Low-temperature heterogeneous catalytic reaction in an electric field is anticipated as a novel approach for on-demand and small-scale catalytic processes. This report quantitatively reveals the important role of proton coverage on the catalyst support for catalytic ammonia synthesis in an electric field, which shows an anti-Arrhenius behaviour.

    DOI PubMed

  • First observation of surface protonics on SrZrO<inf>3</inf> perovskite under a H<inf>2</inf> atmosphere

    Yudai Hisai, Kota Murakami, Yukiko Kamite, Quanbao Ma, Einar Vøllestad, Ryo Manabe, Taku Matsuda, Shuhei Ogo, Truls Norby, Yasushi Sekine

    Chemical Communications   56 ( 18 ) 2699 - 2702  2020.03  [Refereed]

     View Summary

    This journal is © The Royal Society of Chemistry. This is the first direct observation that surface proton hopping occurs on SrZrO3 perovskite even under a H2 (i.e. dry) atmosphere. Understanding proton conduction mechanisms on ceramic surfaces under a H2 atmosphere is necessary to investigate the role of proton hopping on the surface of heterogeneous catalysts in an electric field. In this work, surface protonics was investigated using electrochemical impedance spectroscopy (EIS). To extract the surface proton conduction, two pellets of different relative densities were prepared: a porous sample (R.D. = 60%) and a dense sample (R.D. = 90%). Comparison of conductivities with and without H2 revealed that only the porous sample showed a decrease in the apparent activation energy of conductivity by supplying H2. H/D isotope exchange tests revealed that the surface proton is the dominant conductive species over the porous sample with H2 supply. Such identification of a dominant conductive carrier facilitates consideration of the role of surface protonics in chemical reactions.

    DOI PubMed

  • Recent progress in ethanol steam reforming using non-noble transition metal catalysts: A review

    Shuhei Ogo, Yasushi Sekine

    Fuel Processing Technology   199   106238  2020.03  [Refereed]

     View Summary

    © 2019 Elsevier B.V. Ethanol steam reforming (ESR) is a promising reaction as a sustainable, carbon-neutral hydrogen production process. Because of their high activity and low cost, Co-based and Ni-based catalysts are suitable for industrial ESR processes. Nevertheless, these catalysts present several issues, such as deactivation by coke formation and methane formation as a by-product. This review summarizes the most recent three years works related to ESR for hydrogen production over non-noble transition metal catalysts, exploring their catalytic performance, coke formation, and reaction mechanisms, to provide direction for the development of high-performance catalysts. Findings suggest the particle size and oxidation state of the active metal, acid–base and redox properties of the support, and appropriate promoter selection as important factors to minimize coke and by-product formation.

    DOI

  • Encapsulation of Phase-Changing Eutectic Salts in Magnesium Oxide Fibers for High-Temperature Carbon Dioxide Capture: Beyond the Capacity-Stability Tradeoff

    Monica Louise T. Triviño, Hyeongbin Jeon, Alan Christian S. Lim, Vishwanath Hiremath, Yasushi Sekine, Jeong Gil Seo

    ACS Applied Materials and Interfaces   12 ( 1 ) 518 - 526  2020.01  [Refereed]

     View Summary

    Copyright © 2019 American Chemical Society. Eutectic mixture (EM)-promoted MgO sorbents exhibit high CO2 sorption capacities but experience a significant decrease in uptake after multiple sorption-regeneration cycles due to EM movement and redistribution at high temperatures. Encapsulation of a pseudoliquid, phase-changing EM promoter with MgO may thus prevent the loss of active interface by confining the EM within a fixed area inside a MgO shell. In this work, we successfully embedded an EM composed of KNO3 and LiNO3 in a MgO fiber matrix via core-shell electrospinning. The synthesized sorbent achieved relatively high and steady sorption capacities, maintaining a stable uptake of ∼20 wt % after 25 sorption-regeneration cycles. The sorbent was also characterized using various techniques including in situ transmission electron microscopy (TEM) to describe its morphology, from which it was confirmed that the eutectic salt existed in distributed hollow pockets within the MgO fiber matrix and stayed confined within these fixed areas, favorably limiting its movement and redistribution when exposed to high temperatures where it exists in the liquid form. The EM may also be described as a glue that holds the fiber together, while MgO acts as a protective shell that prevents structural changes and rearrangement caused by EM movement, allowing the sorbent to retain its cyclic stability after multiple cycles and demonstrating its potential for industrial use after further improvement. Thus, the microencapsulation of a phase-changing EM material with pure MgO metal oxide was successfully achieved and might be explored for various material applications.

    DOI PubMed

  • Heteroatom doping effects on interaction of H<inf>2</inf>O and CeO<inf>2</inf> (111) surfaces studied using density functional theory: Key roles of ionic radius and dispersion

    Kota Murakami, Shuhei Ogo, Atsushi Ishikawa, Yuna Takeno, Takuma Higo, Hideaki Tsuneki, Hiromi Nakai, Yasushi Sekine

    Journal of Chemical Physics   152 ( 1 )  2020.01  [Refereed]

     View Summary

    © 2020 Author(s). Understanding heteroatom doping effects on the interaction between H2O and cerium oxide (ceria, CeO2) surfaces is crucially important for elucidating heterogeneous catalytic reactions of CeO2-based oxides. Surfaces of CeO2 (111) doped with quadrivalent (Ti, Zr), trivalent (Al, Ga, Sc, Y, La), or divalent (Ca, Sr, Ba) cations are investigated using density functional theory (DFT) calculations modified for onsite Coulomb interactions (DFT + U). Trivalent (except for Al) and divalent cation doping induces the formation of intrinsic oxygen vacancy (Ovac), which is backfilled easily by H2O. Partially OH-terminated surfaces are formed. Furthermore, dissociative adsorption of H2O is simulated on the OH terminated surfaces (for trivalent or divalent cation doped models) and pure surfaces (for Al and quadrivalent cation doped surfaces). The ionic radius is crucially important. In fact, H2O dissociates spontaneously on the small cations. Although a slight change is induced by doping as for the H2O adsorption energy at Ce sites, the H2O dissociative adsorption at Ce sites is well-assisted by dopants with a smaller ionic radius. In terms of the amount of promoted Ce sites, the arrangement of dopant sites is also fundamentally important.

    DOI PubMed

  • Low-temperature conversion of carbon dioxide to methane in an electric field

    Kensei Yamada, Shuhei Ogo, Ryota Yamano, Takuma Higo, Yasushi Sekine

    Chemistry Letters   49 ( 3 ) 303 - 306  2020  [Refereed]  [International journal]

     View Summary

    © 2020 The Chemical Society of Japan CO2 methanation was conducted at low temperatures with an electric field. Results show that 5 wt %Ru/CeO2 catalyst exhibited high and stable catalytic activity for CO2 methanation with the electric field. The kinetic investigations and in-situ DRIFTS measurements revealed that Ru/CeO2 catalyst promoted CO2 methanation and Ru at the RuCeO2 interface (low-coordinated Ru sites) contributes to the reverse water gas shift reaction at low temperatures in the electric field.

    DOI

  • Low-temperature selective dehydrogenation of methylcyclohexane by surface protonics over Pt/anatase-TiO<inf>2</inf> catalyst

    Misato Kosaka, Takuma Higo, Shuhei Ogo, Jeong Gil Seo, Shigeru Kado, Ken ichi Imagawa, Yasushi Sekine

    International Journal of Hydrogen Energy   45 ( 1 ) 738 - 743  2020.01  [Refereed]

     View Summary

    © 2019 Hydrogen Energy Publications LLC For a liquid organic hydride system used for a hydrogen carrier, methylcyclohexane (MCH)–toluene cycle is promising. In this cycle, dehydrogenation of MCH is an endothermic reaction and a key step. We have conducted dehydrogenation of MCH over Pt/anatase-TiO2 catalyst in an electric field to promote MCH dehydrogenation at a temperature as low as 448 K. The electric field application brought high activity of 37% conversion even at 448 K, exceeding the thermodynamic equilibrium of 12%. This Pt/anatase-TiO2 catalyst showed only a small amount of methane and carbon by-production and showed high activity for 360 min because of surface protonics.

    DOI

  • オンデマンド・低温で駆動可能なアンモニア合成プロセスのための触媒開発

    村上 洸太, 関根 泰

    化学工業   70 ( 11 ) 46 - 51  2019.11

  • Dehydrogenation of Ethane via the Mars-van Krevelen Mechanism over La<inf>0.8</inf>Ba<inf>0.2</inf>MnO<inf>3-Î&amp;acute;</inf> Perovskites under Anaerobic Conditions

    Hikaru Saito, Hirofumi Seki, Yukiko Hosono, Takuma Higo, Jeong Gil Seo, Shun Maeda, Kunihide Hashimoto, Shuhei Ogo, Yasushi Sekine

    Journal of Physical Chemistry C   123 ( 43 ) 26272 - 26281  2019.10  [Refereed]

     View Summary

    Copyright © 2019 American Chemical Society. Dehydrogenation of ethane over perovskite oxide catalysts was investigated using the redox of perovskites and H2O as an oxidizing agent. The La0.8Ba0.2MnO3-Î&acute; (LBMO) perovskite showed a high catalytic activity for dehydrogenation of ethane. Periodic dry (without H2O)-wet (with H2O) operation tests revealed that dehydrogenation of ethane in the presence of H2O over LBMO proceeded via the Mars-van Krevelen (MvK) mechanism. Under the wet condition with D2O instead of H2O, D2 formation was verified, demonstrating that reactive lattice oxygens in LBMO contributed to the dehydrogenation reaction and that they were regenerated by water. Isotopic transient tests with H218O and in situ X-ray absorption fine structure measurements revealed that the reduction and oxidation of Mn in LaMnO3 and LBMO occurred under the reaction atmosphere and that the partial replacement of the La sites with Ba improved the redox ability of Mn, resulting in its high activity. Furthermore, temperature-programmed reduction under H2 elucidated that the reduction of Mn3+ to Mn2+ was promoted by Ba doping. The LBMO perovskite showed the very high activity for dehydrogenation of ethane in the presence of H2O via the MvK mechanism by virtue of the high redox properties of Mn.

    DOI

  • Governing factors of supports of ammonia synthesis in an electric field found using density functional theory

    Kota Murakami, Yuta Tanaka, Sasuga Hayashi, Ryuya Sakai, Yudai Hisai, Yuta Mizutani, Atsushi Ishikawa, Takuma Higo, Shuhei Ogo, Jeong Gil Seo, Hideaki Tsuneki, Hiromi Nakai, Yasushi Sekine

    Journal of Chemical Physics   151 ( 6 ) 64708  2019.08  [Refereed]

     View Summary

    © 2019 Author(s). Efficient ammonia synthesis at low temperatures is anticipated for establishing a hydrogen carrier system. We reported earlier that application of an electric field on the Cs/Ru/SrZrO3 catalyst enhanced catalytic ammonia synthesis activity. It is now clear that N2 dissociation is activated by hopping protons in the electric field. Efficient ammonia synthesis proceeds by an "associative mechanism" in which N2 dissociates via an N2H intermediate, even at low temperatures. The governing factor of ammonia synthesis activity in an electric field for active metals differed from that in the conventional mechanism. Also, N2H formation energy played an important role. The effects of dopants (Al, Y, Ba, and Ca) on this mechanism were investigated using activity tests and density functional theory calculations to gain insights into the support role in the electric field. Ba and Ca addition showed positive effects on N2H formation energy, leading to high ammonia synthesis activity. The coexistence of proton-donating and electron-donating abilities is necessary for efficient N2H formation at the Ru-support interface.

    DOI

  • Effect of Ba addition to Ga-Α-Al<inf>2</inf>O<inf>3</inf> catalyst on structure and catalytic selectivity for dehydrogenation of ethane

    Hirofumi Seki, Hikaru Saito, Kenta Toko, Yukiko Hosono, Takuma Higo, Jeong Gil Seo, Shun Maeda, Kunihide Hashimoto, Shuhei Ogo, Yasushi Sekine

    Applied Catalysis A: General   581 ( 581 ) 23 - 30  2019.07  [Refereed]

     View Summary

    © 2019 Elsevier B.V. Modified Ga-α-Al2O3 catalyst with Ba showed high catalytic activity, selectivity and low carbon formation on catalytic ethane dehydrogenation to ethylene even in the presence of steam. The resultant Ba-Ga-α-Al2O3 (Ba/Ga molar ratio = 0.10) catalyst showed high ethylene selectivity (98%), high activity, and stability. Temperature-programmed oxidation measurements revealed that Ba addition suppressed coke formation at Ga sites. XRD, XAFS and TEM results showed the existence of highly dispersed β-Ga2O3 on the α-Al2O3 support, irrespective of Ba addition. Observation of hydrogen adsorption using FT-IR spectroscopy revealed a decrease in the surface tetrahedrally coordinated Ga (designated as Ga(T)) sites by Ba modification, indicating that the surface Ga(T) sites are covered with Ba. Density functional theory calculation revealed that coke formation through ethylene decomposition is likely to occur at surface Ga(T) sites, and revealed that the addition of an optimal amount of Ba to Ga-α-Al2O3 inhibits coke formation at the surface Ga(T) sites, leading to high ethylene selectivity.

    DOI

  • Electric Field and Mobile Oxygen Promote Low-Temperature Oxidative Coupling of Methane over La<inf>1-x</inf>Ca<inf>x</inf>AlO<inf>3-δ</inf> Perovskite Catalysts

    Ayaka Sato, Shuhei Ogo, Yuna Takeno, Kent Takise, Jeong Gil Seo, Yasushi Sekine

    ACS Omega   4 ( 6 ) 10438 - 10443  2019.06  [Refereed]

     View Summary

    © Copyright 2019 American Chemical Society. Oxidative coupling of methane (OCM) over La1-xMxAlO3-δ (M = Ca, Sr, Ba; x = 0, 0.1, 0.2, 0.3) in an electric field at low temperature (423 K) was investigated. Among the tested catalysts, the La0.7Ca0.3AlO3-δ catalyst showed the highest performance in terms of C2H6 + C2H4 yield (11.1%). Surface mobile oxygen species (O22- or O-), which were considered as active oxygen species for the OCM reaction, increased with increasing Ca doping amount, and thereby the La0.7Ca0.3AlO3-δ catalyst showed the best catalytic activity.

    DOI

  • Role of Electric Field and Surface Protonics on Low-Temperature Catalytic Dry Reforming of Methane

    Tomohiro Yabe, Kensei Yamada, Kota Murakami, Kenta Toko, Kazuharu Ito, Takuma Higo, Shuhei Ogo, Yasushi Sekine

    ACS Sustainable Chemistry and Engineering   7 ( 6 ) 5690 - 5697  2019.03  [Refereed]

     View Summary

    Copyright © 2019 American Chemical Society. The role of the electric field and surface protonics on low temperature catalytic dry reforming of methane was investigated over 1 wt %Ni/10 mol %La-ZrO2 catalyst, which shows very high catalytic activity even at temperatures as low as 473 K. We investigated kinetic analyses using isotope and in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS), and kinetic analyses revealed synergetic effects between the catalytic reaction and the electric field with less than one-fifth the apparent activation energy at low reaction temperatures. Results of kinetic investigations using isotopes such as CD4 and 18O2, in situ DRIFTS in the electric field, and density functional theory calculation indicate that methane dry reforming proceeds well by virtue of surface protonics. CH4 and CO2 were activated by proton collision at the Ni-La-ZrO2 interface based on the "inverse" kinetic isotope effect.

    DOI

  • Steam reforming of aromatic hydrocarbon at low temperature in electric field

    Kent Takise, Ayaka Sato, Keisuke Muraguchi, Shuhei Ogo, Yasushi Sekine

    Applied Catalysis A: General   573 ( 573 ) 56 - 63  2019.03  [Refereed]

     View Summary

    © 2019 Elsevier B.V. Toluene steam reforming was conducted over Ni-supported La0.7Sr0.3AlO3-δ (LSAO) perovskite oxide at 473 K in an electric field, and high toluene conversion was achieved even at such low temperature. Steam reforming is generally done at higher temperatures because of the endothermic nature of this reaction and coke prevention, which requires the contribution of heat energy in great amounts. Reportedly, water activation is particularly difficult to achieve at lower temperatures. Results of kinetic analyses such as Arrhenius plots and partial pressure dependence have revealed that imposing an electric field promotes water activation over Ni/LSAO catalyst. According to steady state isotopic kinetic analysis (SSITKA) and temperature programmed desorption infrared (TPD-IR) measurements, such water activation was accelerated via a redox mechanism using surface lattice oxygen of LSAO. The stimulated mobile lattice oxygen oxidized the adsorbed toluene and formed coke precursor in the electric field. The electric field achieved a lowered reaction temperature for efficient hydrogen production and coke suppression with redox property of LSAO support during toluene steam reforming.

    DOI

  • 電場触媒反応による水素製造,

    鳥本 万貴, 関根 泰

    水素エネルギーシステム   ( 44 ) - 1  2019

  • 卑金属触媒を用いた低温電場アンモニア合成,

    田中 雄太, 村上 洸太, 関根 泰

    ファインケミカル   48 ( 9 ) 12 - 18  2019

  • Irreversible catalytic methylcyclohexane dehydrogenation by surface protonics at low temperature

    Kent Takise, Ayaka Sato, Kota Murakami, Shuhei Ogo, Jeong Gil Seo, Ken Ichi Imagawa, Shigeru Kado, Yasushi Sekine

    RSC Advances   9 ( 11 ) 5918 - 5924  2019  [Refereed]

     View Summary

    © 2019 The Royal Society of Chemistry. Liquid organic hydrides are regarded as promising for use as hydrogen carriers via the methylcyclohexane (MCH)-toluene-hydrogen cycle. Because of the endothermic nature of MCH dehydrogenation, the reaction is usually conducted at temperatures higher than 623 K. In this work, low-temperature catalytic MCH dehydrogenation was demonstrated over 3 wt% Pt/CeO 2 catalyst by application of electric field across a fixed-bed flow reactor. Results show that a high conversion of MCH beyond thermodynamic equilibrium was achieved even at 423 K. Kinetic analyses exhibited a positive correlation of hydrogen to the reaction rates and an "inverse" kinetic isotope effect (KIE), suggesting that accelerated proton hopping with the H atoms of MCH promotes the reaction. Operando analyses and DFT calculation proved that the reverse reaction (i.e. toluene hydrogenation) was suppressed by the facilitation of toluene desorption in the electric field. The electric field promoted MCH dehydrogenation by surface proton hopping, even at low temperatures with an irreversible pathway.

    DOI

  • Ambient-temperature oxidative coupling of methane in an electric field by a cerium phosphate nanorod catalyst

    Ayaka Sato, Shuhei Ogo, Keigo Kamata, Yuna Takeno, Tomohiro Yabe, Tomokazu Yamamoto, Syo Matsumura, Michikazu Hara, Yasushi Sekine

    Chemical Communications   55 ( 28 ) 4019 - 4022  2019  [Refereed]

     View Summary

    © 2019 The Royal Society of Chemistry. CePO4 nanorods with uniform surface Ce sites could work as a durable catalyst and showed the highest C2 yield of 18% in an electric field without the need for external heating, which was comparable to that reported for high-performance catalysts at high temperature (>900 K).

    DOI PubMed

  • Evaluation of the structure and strength of coke with HPC binder under various preparation conditions

    Yasushi Sekine, Hidekazu Fujimoto

    ISIJ International   59 ( 8 ) 1437 - 1439  2019  [Refereed]

     View Summary

    © 2019 ISIJ Hypercoal (HPC) is examined as a caking additive to the mixture of strongly coking coal and non-slightly coking coal. Samples were coked, then their strength and crystallinity of the carbon structure by Raman spectra were measured. Hypercoal addition increased strength of coke, and a good correlation was observed between the mechanical strength of coke and the Raman parameter defined by the ratio of D3-band to G-band. Results suggest that mutual melting between blended coal and HPC brought strong carbonaceous structure with highly crystallized. The Raman parameter can predict the coke strength to some extent.

    DOI

  • Enhanced methane activation on diluted metal-metal ensembles under an electric field: Breakthrough in alloy catalysis

    Maki Torimoto, Shuhei Ogo, Danny Harjowinoto, Takuma Higo, Jeong Gil Seo, Shinya Furukawa, Yasushi Sekine

    Chemical Communications   55 ( 47 ) 6693 - 6695  2019  [Refereed]

     View Summary

    © 2019 The Royal Society of Chemistry. Methane activation on diluted metal ensembles is a challenging task in the field of alloy chemistry. This report describes that synergy between an electric field and Pd-Zn alloy allows improved catalytic activities in the steam reforming of methane. Because of surface protonics, Pd-Pd ensembles are no longer needed. Ligand effects facilitate methane conversion.

    DOI PubMed

  • Perovskite lattice oxygen contributes to low-temperature catalysis for exhaust gas cleaning

    Takuma Higo, Kohei Ueno, Yuki Omori, Hiroto Tsuchiya, Shuhei Ogo, Satoshi Hirose, Hitoshi Mikami, Yasushi Sekine

    RSC Advances   9 ( 39 ) 22721 - 22728  2019  [Refereed]

     View Summary

    © 2019 The Royal Society of Chemistry. A Pd catalyst supported on Ba-substituted LaAlO3 perovskite (Pd/La0.9Ba0.1AlO3-δ) was investigated for NO reduction at low temperature by propylene, which revealed that Pd/La0.9Ba0.1AlO3-δ has remarkably higher activity than other Pd catalysts at low temperatures (≤573 K) for NO reduction by propylene. To elucidate the surface reaction pathway, transient response tests were conducted using 18O2. Also, X-ray photoelectron spectroscopy (XPS) and diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) measurements were conducted. Comparison with a Ba-impregnated catalyst (Pd/Ba/LaAlO3) demonstrated that Pd/La0.9Ba0.1AlO3-δ shows higher activity for the formation of oxygenated species (CxHyOz) as an intermediate for NO reduction because the surface lattice oxygen has improved mobility via Ba2+ substitution in LaAlO3. Therefore, Pd/La0.9Ba0.1AlO3-δ have high activity for NO reduction, even at low temperatures in a humid condition.

    DOI

  • Low-temperature heterogeneous catalytic reaction by surface protonics

    Maki Torimoto, Kota Murakami, Yasushi Sekine

    Bulletin of the Chemical Society of Japan   92 ( 10 ) 1785 - 1792  2019  [Refereed]

     View Summary

    © 2019 The Chemical Society of Japan Heterogeneous catalytic reaction at low temperatures (<500 K) has been proposed and investigated by our group. As described in this report, recent trends of low-temperature catalytic reaction for hydrogen production by reforming and ammonia synthesis are summarized. Furthermore, our findings obtained using surface protonics for these two reactions are introduced. Surface protonics occurs by application of an electric field to a heterogeneous catalyst. It makes low-temperature catalytic reactions possible for hydrogen production and ammonia synthesis.

    DOI

  • Low-temperature selective catalytic dehydrogenation of methylcyclohexane by surface protonics

    Kent Takise, Ayaka Sato, Shuhei Ogo, Jeong Gil Seo, Ken-ichi Imagawa, Shigeru Kado, Yasushi Sekine

    RSC Advances   9 ( 48 ) 27743 - 27748  2019  [Refereed]

     View Summary

    <p>Electric field facilitated MCH dehydrogenation at 423 K without methane and coke by-production over Pt/TiO2 catalyst by surface protonics.</p>

    DOI

  • Low temperature hydrogen production by ethanol steam reforming over supported metal catalysts in an electric field

    Shuhei Ogo, Yasushi Sekine

    Journal of the Japan Petroleum Institute   62 ( 6 ) 264 - 271  2019  [Refereed]

     View Summary

    A novel electrocatalytic reaction system that involves catalytic reaction in an electric field, for low-temperature catalytic ethanol steam reforming using low-grade waste heat for H2 production, was developed. The application of an electric field to Pt/CeO2 catalyst enabled the reaction to proceed even at 423 K, at which a conventional catalytic reaction only slightly proceeded. Results of activity tests conducted using isotopes revealed that the electric field contributed to activation of the adsorbed OHx species. In-situ DRIFTS measurements revealed that an electric field promoted the formation of reactive adsorbed intermediate acetate species and showed that the steam reforming reaction of the formed acetate species proceeded even at low temperatures. Results showed that ethanol steam reforming proceeded efficiently in the electric field at low temperatures. In this electrocatalytic reaction system, H2 was produced efficiently from ethanol using less electricity, even at low temperature. Applying the electric field lowered the apparent activation energy of three elementary reactions, namely ethanol dehydrogenation, acetaldehyde decomposition, and acetaldehyde steam reforming. In particular, the electric field preferentially promoted acetaldehyde steam reforming. Energy demand for H2 production in this electrocatalytic process was sufficiently low, at 79 MJ/kg H2, which was about half of the combustion enthalpy of hydrogen.

    DOI

  • Production, storage, utilization of hydrogen,

    Kent Takise, Yasushi Sekine

    Acc. Mater. Surf. Res.   4 ( 3 ) 115 - 134  2019

  • Ni-Mg Supported Catalysts on Low-Temperature Electrocatalytic Tri-reforming of Methane with Suppressed Oxidation

    Tomohiro Yabe, Kensei Yamada, Task Oguri, Takuma Higo, Shuhei Ogo, Yasushi Sekine

    ACS Catalysis   8 ( 12 ) 11470 - 11477  2018.12  [Refereed]

     View Summary

    © 2018 American Chemical Society. 10wt%Ni-10wt%Mg-La0.1Zr0.9O2-x (LZO) catalyst shows high reforming activity of methane while suppressing methane combustion on tri-reforming of methane at low temperatures of 473 K in an electric field. On the basis of results of light-on and light-off tests for methane oxidation and temperature dependencies for catalytic methane steam reforming activity with or without the electric field, we found that Mg addition to 10wt%Ni-LZO catalyst suppresses methane combustion, while the methane steam reforming proceeds well by virtue of surface protonics in the electric field. Ni2+ on 10wt%Ni-10wt%Mg-LZO catalyst was more cationic than that on 10wt%Ni-LZO catalyst, and NiO-MgO solid solution formed on LZO support played an important role in combustion suppression.

    DOI

  • Methane conversion using carbon dioxide as an oxidizing agent: A review

    Tomohiro Yabe, Yasushi Sekine

    Fuel Processing Technology   181 ( 181 ) 187 - 198  2018.12  [Refereed]

     View Summary

    © 2018 Elsevier B.V. Recent trends on the direct conversion of methane, employing carbon dioxide as an oxidizing agent are reviewed. While oxidation using molecular oxygen involves the sequential oxidation of various intermediates to generate carbon dioxide and exhibits low selectivity for the desired products, methane activation using carbon dioxide as an oxidant eliminates this sequential oxidation and has considerable promise. In this context, supported metal catalysts can promote the dry reforming of methane, and structured oxide catalysts have been found to enable methane coupling to C2 products, using carbon dioxide as the oxidizing agent. This review also summarizes recent research regarding the use of nonconventional processes for methane activation in conjunction with carbon dioxide.

    DOI

  • Theoretical investigation on structural effects of Pt–Mn catalyst on activity and selectivity for methylcyclohexane dehydrogenation

    Shota Manabe, Tomohiro Yabe, Atsushi Nakano, Satoshi Nagatake, Takuma Higo, Shuhei Ogo, Hiromi Nakai, Yasushi Sekine

    Chemical Physics Letters   711 ( 711 ) 73 - 76  2018.11  [Refereed]

     View Summary

    © 2018 Elsevier B.V. The structure of Pt-Mn/Al2O3 catalyst which shows high performance for dehydrogenation of methylcyclohexane, a prospective hydrogen carrier, was investigated by XAFS and DFT calculations. Mn addition on Pt/Al2O3 brings higher activity, selectivity, and stability for dehydrogenation of MCH than with Pt/Al2O3 alone. Results of XAFS and DFT calculations revealed that MnOx selectively covered the unsaturated coordination of Pt. On the unsaturated step facets such as Pt (1 1 0) and Pt (3 1 1), demethylation proceeds easily. Addition of Mn on Pt/Al2O3 catalyst brought selective dehydrogenation of MCH by coverage of such step sites with MnOx.

    DOI

  • Steam reforming of dimethyl ether promoted by surface protonics in an electric field

    Reona Inagaki, Ryo Manabe, Yudai Hisai, Yukiko Kamite, Tomohiro Yabe, Shuhei Ogo, Yasushi Sekine

    International Journal of Hydrogen Energy   43 ( 31 ) 14310 - 14318  2018.08  [Refereed]

     View Summary

    © 2018 Hydrogen Energy Publications LLC The catalytic steam reforming of dimethyl ether (DME) in an electric field was carried out and the effects of proton hopping induced by the electric field on a Pd-supported CeO2 catalyst surface were investigated. The hydrolysis of DME was promoted even on Pd/CeO2 catalyst by the application of the electric field at low temperatures (in the range of 423–623 K), while the direct decomposition of DME was suppressed. The apparent activation energy in this temperature range was much lower with (17.2 kJ mol−1) than without (79.0 kJ mol−1) the electric field. Kinetic analyses demonstrated that the effect of the reactant partial pressures was also markedly different with and without the electric field. The effect of the partial pressure of water and electrochemical impedance spectra strongly suggest that surface proton hopping promotes the steam reforming of DME in an electric field at low temperatures.

    DOI

  • Ammonia Synthesis Over Co Catalyst in an Electric Field

    Ami Gondo, Ryo Manabe, Ryuya Sakai, Kota Murakami, Tomohiro Yabe, Shuhei Ogo, Masatoshi Ikeda, Hideaki Tsuneki, Yasushi Sekine

    Catalysis Letters   148 ( 7 ) 1929 - 1938  2018.07  [Refereed]

     View Summary

    © 2018, Springer Science+Business Media, LLC, part of Springer Nature. Abstract: Ammonia is an important chemical feedstock and is produced by Ru or Fe catalyst so far. We investigated Co catalyst for low temperature ammonia synthesis in an electric field. Well-reduced Co/Ce0.5Zr0.5O2 catalyst showed high activity for ammonia synthesis even at 473 K in the electric field. Various characterizations including kinetic tests, operando DRIFTS measurements, TEM observations, and XAFS measurements, revealed that the active site is the interface between supported Co and Ce0.5Zr0.5O2 oxide support, thanks to the surface protonics derived from an electric field. Graphical Abstract: [Figure not available: see fulltext.].

    DOI

  • Methane dissociative adsorption in catalytic steam reforming of methane over Pd/CeO<inf>2</inf> in an electric field

    S. Okada, R. Manabe, R. Inagaki, S. Ogo, Y. Sekine

    Catalysis Today   307 ( 307 ) 272 - 276  2018.06  [Refereed]

     View Summary

    © 2017 Elsevier B.V. To elucidate the reaction mechanism of catalytic steam reforming of methane in an electric field, operando–diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) has been used to investigate methane dissociative adsorption at low temperatures using CH4, H2O, and their isotopes. Operando-analyses demonstrated that methane was adsorbed and converted into CO and CO2 more when CD4 and/or D2O was used instead of CH4 and/or H2O. This observed “inverse” kinetic isotope effect is based on the difference of C–H–H vibrational energy level at the transition state. Furthermore, CO2-methanation, which is the reverse reaction of steam reforming of methane, was irreversible with H2O in an electric field. These results demonstrate that the proton collision promoted methane activation irreversibly, even at low temperatures in an electric field.

    DOI

  • Elucidation of the role of electric field on low temperature ammonia synthesis using isotopes

    Kota Murakami, Ryo Manabe, Hideaki Nakatsubo, Tomohiro Yabe, Shuhei Ogo, Yasushi Sekine

    Catalysis Today   303 ( 303 ) 271 - 275  2018.04  [Refereed]

     View Summary

    © 2017 Elsevier B.V. We have found that an electric field brings high yield on low temperature catalytic ammonia synthesis over Cs/Ru/SrZrO3 catalyst. The role of the electric field is investigated based on kinetics and isotope effects.Results show that the electric field promotes proton hopping on the catalyst surface, and it brings a change in the reaction mechanism from the conventional one to the N2H+ intermediate mechanism. In the electric field, N2H+ intermediate plays an important role, enabling low-temperature ammonia synthesis.

    DOI

  • Evaluating surface protonic transport on cerium oxide via electrochemical impedance spectroscopy measurement

    Ryo Manabe, Sindre Østby Stub, Truls Norby, Yasushi Sekine

    Solid State Communications   270 ( 270 ) 45 - 49  2018.02  [Refereed]

     View Summary

    © 2017 Elsevier Ltd Surface protonic transport on cerium oxide (CeO2) was investigated using electrochemical impedance spectroscopy (EIS). CeO2 pellets showing low relative density: approximately 60%, was prepared for the purpose. The structure and morphology of the prepared CeO2 pellets were confirmed from XRD and SEM measurements. Results show that the pellets had a pure cubic phase, with open pores on which water can be adsorbed. Electrochemical impedance spectroscopy measurements were taken to evaluate the surface protonic transport on CeO2 as a function of temperature and as a function of partial pressure of water (PH2O) at 400 °C. Investigations of the temperature dependence of the conductivity revealed that only the conductivities of surface grain bulk (σintra) and surface grain boundary (σinter) increased with decreasing temperatures under wet conditions (PH2O = 0.026 atm). The PH2O dependence of surface conductivities (σintra and σinter) revealed that σintra increases strongly with PH2O at 400 °C. These findings provide evidence that water adsorbates play an important role in surface protonic transport on CeO2 at low temperatures. Surface protonic transport at low temperatures can contribute to the expansion of applications for electrical and catalytic processes.

    DOI

  • Electron-Hopping Brings Lattice Strain and High Catalytic Activity in the Low-Temperature Oxidative Coupling of Methane in an Electric Field

    Shuhei Ogo, Hideaki Nakatsubo, Kousei Iwasaki, Ayaka Sato, Kota Murakami, Tomohiro Yabe, Atsushi Ishikawa, Hiromi Nakai, Yasushi Sekine

    Journal of Physical Chemistry C   122 ( 4 ) 2089 - 2096  2018.02  [Refereed]

     View Summary

    © 2018 American Chemical Society. Detailed reaction mechanisms for the oxidative coupling of methane (OCM) over Ce2(WO4)3 catalysts at low temperatures in an electric field were investigated. The influence of Ce cations in the Ce2(WO4)3 catalyst was evaluated by comparing the OCM activity over various Ln2(WO4)3 (Ln = La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, and Dy) catalysts in an electric field. The electronic states of Ln and W cations and the relationship between the distorted Ce2(WO4)3 structure and methane activation were examined using X-ray absorption fine structure (XAFS) measurements and first-principles calculations. The results reveal that the Ln2(WO4)3 catalysts with redox-active Ln cations (Ce, Pr, Sm, Eu, and Tb) show OCM activity. First-principles calculations indicate that Ce3+ species in the Ce2(WO4)3 structure are oxidized to Ce4+ species in an electric field by extracting electrons from the Ce 4f orbitals near the Fermi level; as a result, its structure is distorted. The results indicate that the redox reaction of Ln cations in Ln2(WO4)3 induced by an electric field brings lattice strain and a high OCM activity in an electric field.

    DOI

  • Catalytic oxidative conversion of methane and ethane over polyoxometalate-derived catalysts in electric field at low temperature

    Shuhei Ogo, Kousei Iwasaki, Kei Sugiura, Ayaka Sato, Tomohiro Yabe, Yasushi Sekine

    Catalysis Today   299   80 - 85  2018.01  [Refereed]

     View Summary

    © 2017 Elsevier B.V. We examined oxidative coupling of methane (OCM) and oxidative dehydrogenation of ethane (ODE) over various polyoxometalate supported CeO2 catalysts at 423 K in an electric field. Tetrabutylammonium (TBA) salt of Keggin-type phosphotungstate (PW12O40) supported CeO2 catalysts ((TBA)3PW12O40/CeO2) showed high activities for OCM and ODE in the electric field (3 mA) at 423 K, although the catalyst without the electric field showed extremely low activities at such low temperature. FT-IR spectra and XRD patterns confirmed that the structure of (TBA)3PW12O40/CeO2 was changed to Ce2(WO4)3/CeO2 after reactions with the electric field, and it acted as an active site structure for OCM and ODE with the electric field. Results of activity tests revealed that the C2H6 production was a main reaction in OCM with the electric field, and C2H4 was formed through a successive oxidative dehydrogenation of the formed C2H6. Periodic operation tests demonstrated that reactive oxygen species suitable for ODE were formed on the catalyst surface of Ce2(WO4)3 in the electric field.

    DOI

  • メタン・二酸化炭素・水素のための触媒

    小河 脩平, 矢部 智宏, 関根 泰

    化学と教育   ( 2 ) 68 - 71  2018

  • シフト反応における貴金属系触媒のシンタリング

    関根 泰

    触媒劣化—原因、対策と長寿命触媒開発—, シーエムシー出版     58 - 61  2018

  • 触媒利用による水素製造

    瀧瀬 賢人, 稲垣 玲於奈, 関根 泰

    防錆管理   ( 62(2) ) 63 - 68  2018

  • 電場触媒反応を利用した低温域で進むアンモニア合成

    村上 洸太, 関根 泰

    化学工業   ( 6 ) 403 - 408  2018

  • エチレン低温合成のための新手法

    小河脩平, 関根 泰

    配管技術   ( 9 ) 5 - 9  2018

  • Pt/CeO2触媒を用いた低温電場中でのエタノール水蒸気改質による水素製造

    小河脩平, 関根 泰

    ペトロテック   ( 9 ) 695 - 700  2018

  • 低温下でのメタン酸化カップリング

    小河脩平, 佐藤綾香, 関根 泰

    クリーンエネルギー   ( 11 ) 13 - 18  2018

  • 低温下でのメタン酸化カップリングの反応メカニズム

    小河脩平, 矢部智宏, 関根 泰

    ペトロテック   ( 11 ) 877 - 886  2018

  • Preferential dealumination of Zn/H-ZSM-5 and its high and stable activity for ethane dehydroaromatization

    Hikaru Saito, Satoshi Inagaki, Kiria Kojima, Qiao Han, Tomohiro Yabe, Shuhei Ogo, Yoshihiro Kubota, Yasushi Sekine

    Applied Catalysis A: General   549 ( 549 ) 76 - 81  2018  [Refereed]

     View Summary

    © 2017 Elsevier B.V. The effect of steam treatment on Zn/H-ZSM-5 catalysts prepared by an ion-exchange method for non-oxidative ethane dehydroaromatization was investigated. Steam treatment of Zn/H-ZSM-5 after Zn loading improved its catalytic stability on aromatic hydrocarbon formation including benzene, toluene and xylene. Temperature programmed oxidation measurements demonstrated that the steam treatment brought suppression of coke formation and it contributed to the improvement in the catalytic stability. Characterization of the local structure of the zeolites by 27Al and 29Si magic angle spinning nuclear magnetic resonance (MAS NMR) spectroscopy revealed that dealumination of the framework Al in the MFI structure proceeded by steam treatment. Results of temperature programmed desorption of ammonia indicate the decrease in the amount of acid sites by the steam treatment. The slight changes in Zn content and its electronic state indicated that bared Al related with H+, not with Zn2+, in the MFI structure was preferentially dealuminated by steam treatment. The preferential dealumination led to suppression of coke formation by the selective removal of undesirable Brønsted acid sites.

    DOI

  • Selective Adsorption of Toluene on Perovskite-type Oxide

    Tomohiro Suzuki, Keiri Shiono, Shota Manabe, Tomohiro Yabe, Takuma Higo, Shuhei Ogo, Yasushi Serine

    Journal of the Japan Petroleum Institute   61 ( 5 ) 272 - 281  2018  [Refereed]

     View Summary

    Organic chemical hydrides are one of the most potential methods for hydrogen storage, however, aromatic compound remains unreacted after the hydrogenation process due to equilibrium limitations. To address this, a solid-state adsorbent which could selectively adsorb toluene from methylcyclohexane - toluene mixture was developed. Several La-based oxides were tested and La0.8Ba0.2CoO3-d (LBCO) exhibited high adsorption and selectivity for toluene. Analyses of the electronic state and adsorption state of toluene found part of the Co ions in the LBCO lattice were Co4+. The high oxidation state of Co4+ in the LBCO lattice and surface lattice oxygen mediates the selective adsorption of toluene.

    DOI

  • Hydrogen production by water decomposition through redox reaction of ce-based metal oxide systems in electric field

    Kentaro Ogino, Yusuke Sasaki, Yutaro Kurosawa, Shuhei Ogo, Tomohiro Yabe, Wakichi Kondo, Taisuke Ono, Kunihiro Kojima, Yasushi Sekine

    Chemistry Letters   47 ( 5 ) 643 - 646  2018  [Refereed]

     View Summary

    © 2018 The Chemical Society of Japan. We investigated a highly active hydrogen production system by decomposition of water through the redox reaction of metal oxide at 623 K in an electric field (EF). Although Ce0.67Cr0.33O2 oxide showed high activity in the EF for oxygen release with the formation of lattice oxygen defects, it showed no hydrogen production activity by the regeneration of lattice oxygen defects with water. However, addition of Pd into the Ce0.67Cr0.33O2 structure promoted the hydrogen formation rate while maintaining its oxygen release activity. Results of optimization of the doping Pd amount demonstrated that 5 mol% Pd-doped oxide (Ce0.62Cr0.33Pd0.05O2) had the highest oxygen release rate and hydrogen formation rate. Doped Pd contributes to lattice strain induction and thereby increases the reaction rates.

    DOI

  • Dehydrogenation of Methylcyclohexane over Pt/TiO2-Al2O3 Catalysts

    Yukihiro Sugiura, Tomomi Nagatsuka, Kouichi Kubo, Yuichiro Hirano, Akitoshi Nakamura, Kazunori Miyazawa, Yusuke Iizuka, Satoshi Furuta, Hideshi Iki, Takuma Higo, Yasushi Sekine

    Chemistry Letters   46 ( 11 ) 1601 - 1604  2017.11  [Refereed]

    DOI

  • Catalytic Reaction Assisted by Plasma or Electric Field

    Shuhei Ogo, Yasushi Sekine

    Chemical Record   17 ( 8 ) 726 - 738  2017.08  [Refereed]

     View Summary

    © 2017 The Chemical Society of Japan & Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim Direct conversion of methane, other hydrocarbons, and alcohol at lower temperatures can be achieved using plasma or an electric field and catalysts. Non-equilibrium plasma enables activation of stable molecules including methane, carbon dioxide, and water, even at low temperatures, by virtue of high electron energy. Use of a hybrid system of plasma and catalyst provided high conversion and selectivity to products by virtue of adsorption on the catalyst. Imposing a DC electric field to the catalyst bed also promotes catalytic reactions, even at low temperatures. Two mechanisms for electro-catalytic reactions are proposed for the DC electric field imposition: reactant activation by surface protonics and production of active surface oxygen species on the catalyst. This review presents summaries of these novel processes.

    DOI PubMed

  • Low-temperature oxidative coupling of methane in an electric field using carbon dioxide over Ca-doped LaAlO<inf>3</inf> perovskite oxide catalysts

    Tomohiro Yabe, Yukiko Kamite, Kei Sugiura, Shuhei Ogo, Yasushi Sekine

    Journal of CO2 Utilization   20   156 - 162  2017.07  [Refereed]

     View Summary

    © 2017 Elsevier Ltd. Methane conversion was conducted over various perovskite oxide catalysts at 423 K using carbon dioxide as an oxidant in an electric field. La0.7Ca0.3AlO3-δ catalyst showed high CO2-OCM activity. The highest CO2-OCM activity, C2 yield of 7.4%, was obtained even at 348 K, that value was higher than those of other earlier reports. Dry reforming of methane to produce syngas (H2 + CO) proceeded simultaneously, and no other byproduct was observed. Results of in-situ IR, XRD and TG measurements demonstrated that CO2 adsorption on the catalyst surface and formation of La2O2CO3 intermediate are important for progress of the CO2-OCM reaction, even at low temperature in an electric field. Ca atom incorporated in LaAlO3 perovskite played an important role in C2 hydrocarbon formation.

    DOI

  • Promotive effect of Ba addition on the catalytic performance of Ni/LaAlO<inf>3</inf> catalysts for steam reforming of toluene

    Takuma Higo, Hikaru Saito, Shuhei Ogo, Yukihiro Sugiura, Yasushi Sekine

    Applied Catalysis A: General   530   125 - 131  2017.01  [Refereed]

     View Summary

    © 2016 Elsevier B.V. Ba addition to supported Ni catalysts was investigated on steam reforming of toluene, as a model compound of biomass tar. Ba addition showed drastic promotive effects on catalytic activity and tolerance against oxidation. Various catalytic tests and characterization were conducted, including pressure dependence, Arrhenius plots, STEM and XAFS observations, dispersion of supported Ni, and temperature programmed reduction. Results revealed that the electron donation from Ba to Ni enabled high catalytic performance of Ba/Ni/LaAlO3 perovskite catalyst.

    DOI

  • O-22 Development of an active catalyst for one pot direct catalytic conversion of cellulose to C3 and C4 hydrocarbons

    SEKINE Hikaru, OKUNO Yutaro, ONDA Ayumu, OGO Shuhei, SEKINE Yasushi

    Proceedings of the Conference on Biomass Science   12   43 - 44  2017

     View Summary

    <p>One-pot direct catalytic conversion of cellulose to light hydrocarbons at low temperature (443 K) in the presence of Pt– zeolite catalysts and water was investigated. Results revealed that Pt supported on H+-form ultra stable Y type (H-USY) zeolite catalyst (Pt/H-USY) enabled direct conversion of cellulose into C3 and C4 hydrocarbons without hydrogen and other expensive reagents. The production trend is attributable to the bifunctional catalysis of supported Pt and acid site in H-USY zeolite, which has a large pore system and effective acidity. Results revealed that 1wt% Pt/NH4-USY(14) catalyst showed higher C3+C4 hydrocarbon yield than 1wt% Pt/H-USY(14) catalyst because 1wt% Pt/NH4-USY(14) has smaller Pt particle size and larger Pt surface area. Pt/zeolite catalyst with about 5 nm Pt particle size showed high TOF of C3+C4 hydrocarbon yield.</p>

    DOI CiNii

  • No.1-5 Catalytic conversion of biomass cellulose into C3-C4 hydrocarbons over Pt supported catalyst

    OKUNO Yutaro, SEKINE Hikaru, ONDA Ayumu, YABE Tomohiro, OGO Shuhei, SEKINE Yasushi

    Proceedings of Conference on Coal Science   54   10 - 11  2017

     View Summary

    <p>Catalytic reaction of biomass cellulose into C3 and C4 light hydrocarbons over Pt supported catalyst was investigated. Pt supported on NH4+-form ultra-stable Y type (NH4-USY) zeolite catalyst (Pt/NH4-USY) enabled direct conversion of cellulose into C3 and C4 hydrocarbons without hydrogen and other expensive reagents. Results revealed that 1wt%Pt/NH4-USY(14) catalyst showed higher C3+C4 hydrocarbon yield than 1wt%Pt/H-USY(14). The yield reached 14.5C-% during reaction over the 1wt%Pt/NH4-USY(14) at 443 K for 72 h reaction. Furthermore, because of their structural sensitivity, Pt/zeolite catalysts with Pt particle larger than 5 nm showed higher TOF values than catalysts with Pt particle smaller than 5 nm. The high index {311} facet was observed on Pt particles only when the Pt particle size was 5 nm or larger, suggesting that hydrocarbon formation mainly proceed over the facet.</p>

    DOI CiNii

  • Supported Ga-oxide catalyst for dehydrogenation of ethane

    Hikaru Saito, Shun Maeda, Hirofumi Seki, Shota Manabe, Yuji Miyamoto, Shuhei Ogo, Kunihide Hashimoto, Yasushi Sekine

    Journal of the Japan Petroleum Institute   60 ( 5 ) 203 - 210  2017  [Refereed]

     View Summary

    Dehydrogenation catalysts were analyzed to improve the performance of the ethane cracking tube. Ga, Ge, In, and Sn were studied as dehydrogenation catalysts. Catalytic activity tests showed that the Ga catalyst has the best performance among them. Because the γ-Al2O3 supported Ga catalyst calcined at 1323 K showed high catalytic activity and stability, the structure and the role of Ga using BET, XRD, TEM-EDX, and XAFS measurements were studied. Screening results revealed that the Ga catalyst exhibited a high ethylene formation rate and better ethylene selectivity.

    DOI

  • メタンと空気から低温でC2炭化水素を作り出す

    小河脩平, 佐藤綾香, 矢部智宏, 関根 泰

    触媒   59 ( 6 ) 319 - 324  2017  [Refereed]  [Invited]

  • Combustion suppression in tri-reforming of methane over Ni supported catalysts at low temperatures in electric field

    Task Oguri, Kei Sugiura, Tomohiro Yabe, Shuhei Ogo, Yasushi Sekine

    Journal of the Japan Petroleum Institute   60 ( 5 ) 232 - 240  2017  [Refereed]

     View Summary

    Tri-reforming of CH4 for syngas production was studied over Ni supported catalysts in an electric field at low temperature of 473 K. The main objective is to gain enthalpy from exhaust gases of automobiles using an exhaust gas recirculation system, so high CH4 conversion and low combustion were anticipated. Results showed that La0.1Zr0.9O2 catalyst was the most appropriate support in the electric field. Also, Results showed that the addition of Mg to Ni-supported catalyst suppressed CH4 combustion.

    DOI

  • 電場を利用した化学反応,

    真鍋 亮, 関根 泰

    現代化学   553   20 - 24  2017  [Refereed]

  • 中低温域で作動する固体イオニクス材料と触媒反応,

    矢部 智宏, 関根 泰

    化学   72 ( 8 ) 70 - 71  2017  [Refereed]

  • Nanostructural control of the formation of carbon particles by application of a moderate electric field

    Kei Mukawa, Naganobu Oyama, Toshitaka Shinmi, Yasushi Sekine

    Chemistry Letters   46 ( 1 ) 19 - 21  2017  [Refereed]

     View Summary

    © 2017 The Chemical Society of Japan. Pyrolysis of propylene in a DC electric field was investigated. The resulting nanostructure of carbon particles differs drastically depending on the electrode potential. It indicates that regulating ion species in hydrocarbon pyrolysis presents a means to control the nanoform of carbon particles.

    DOI

  • Low-temperature dry reforming of methane to produce syngas in an electric field over La-doped Ni/ZrO<inf>2</inf>catalysts

    Tomohiro Yabe, Kenta Mitarai, Kazumasa Oshima, Shuhei Ogo, Yasushi Sekine

    Fuel Processing Technology   158   96 - 103  2017  [Refereed]

     View Summary

    © 2016 Elsevier B.V. Dry reforming of methane (DRM) was conducted over various transition metal supported ZrO2catalysts in an electric field. Catalyst of 1wt%Ni/10 mol%La-ZrO2showed high DRM activity even at 423 K of external temperature, at which no DRM proceeds in the conventional catalytic systems. By virtue of the low reaction temperature, low amounts of carbon deposition were confirmed even in conditions of high CH4conversion in the electric field. The imposed electric power was correlated to with the catalytic activities in the electric field. Syngas is producible at low temperature with high energy efficiency.

    DOI

  • Coke resistance of Sr-hydroxyapatite supported Co catalyst for ethanol steam reforming

    Shuhei Ogo, Shun Maeda, Yasushi Sekine

    Chemistry Letters   46 ( 5 ) 729 - 732  2017  [Refereed]

     View Summary

    © 2017 The Chemical Society of Japan. Co/Sr-hydroxyapatite catalyst (Co/Sr10(PO4)6(OH)2: Co/ Sr-P) shows high activity and low carbon formation on ethanol steam reforming. H2-TPR measurements revealed that the Co species supported on Co/Sr-P was reduced only slightly more than that on typical Co/α-Al2O3. XAFS measurements revealed that Co2+ species was observed mainly on the Co/Sr-P catalyst after H2-reduction at reaction temperature of 823 K. Co2+, i.e. CoO particle, on Co/Sr-P catalyst plays an important role as an active site for ethanol steam reforming with high coke resistance.

    DOI

  • Anchoring effect and oxygen redox property of Co/La<inf>0.7</inf>Sr<inf>0.3</inf>AlO<inf>3-Δ</inf> perovskite catalyst on toluene steam reforming reaction

    Kent Takise, Shota Manabe, Keisuke Muraguchi, Takuma Higo, Shuhei Ogo, Yasushi Sekine

    Applied Catalysis A: General   538   181 - 189  2017  [Refereed]

     View Summary

    © 2017 Elsevier B.V. To elucidate specific functions of supports, we investigated steam reforming of toluene as a model compound of biomass tar over Co catalyst supported on perovskite-type oxide. Co-supported La0.7Sr0.3AlO3-δ catalyst showed the highest activity among various Co-supported catalysts. STEM measurements and XPS measurements revealed the coexistence of La cation and lattice oxygen defect produces an anchoring effect to Co particles. The lattice oxygen release rate on each catalyst was measured with H218O steady-state isotopic transient kinetic analysis (SSITKA). The anchoring effect, higher dispersion of Co and redox property, are important for the high catalytic performance of Co/La0.7Sr0.3AlO3-δ catalyst on toluene steam reforming.

    DOI

  • Electrocatalytic synthesis of ammonia by surface proton hopping

    R. Manabe, H. Nakatsubo, A. Gondo, K. Murakami, S. Ogo, H. Tsuneki, M. Ikeda, A. Ishikawa, H. Nakai, Y. Sekine

    Chemical Science   8 ( 8 ) 5434 - 5439  2017  [Refereed]

     View Summary

    <p>We accomplished efficient electrocatalytic low-temperature ammonia synthesis with the highest yield reported to date.</p>

    DOI

  • Effects of Mn addition on dehydrogenation of methylcyclohexane over Pt/Al<inf>2</inf>O<inf>3</inf> catalyst

    Atsushi Nakano, Shota Manabe, Takuma Higo, Hirofumi Seki, Satoshi Nagatake, Tomohiro Yabe, Shuhei Ogo, Tomomi Nagatsuka, Yukihiro Sugiura, Hideshi Iki, Yasushi Sekine

    Applied Catalysis A: General   543   75 - 81  2017  [Refereed]

     View Summary

    © 2017 Elsevier B.V. Methylcyclohexane (MCH) is a prospective hydrogen carrier candidate. Although Pt/Al2O3 catalyst shows high conversion for dehydrogenation of MCH at 623 K, methane formation and deactivation caused by coke deposition are issues over the catalyst. Results of this study demonstrate that Mn addition to Pt/Al2O3 brought higher selectivity and stability for dehydrogenation of MCH than with Pt/Al2O3 alone. Although Pt and Mn do not form an alloy structure, Pt and Mn form an adjacent structure, and the unsaturated coordination of Pt which promotes methane formation and deactivation decreased. Pt-Mn/Al2O3 shows high catalytic performance by virtue of the coverage of such sites by MnOx.

    DOI

  • Low-Temperature Direct Catalytic Hydrothermal Conversion of Biomass Cellulose to Light Hydrocarbons over Pt/Zeolite Catalysts

    Shuhei Ogo, Yutaro Okuno, Hikaru Sekine, Shota Manabe, Tomohiro Yabe, Ayumu Onda, Yasushi Sekine

    ChemistrySelect   2 ( 22 ) 6201 - 6205  2017  [Refereed]

     View Summary

    © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim Direct catalytic hydrothermal conversion of cellulose to C3+C4 hydrocarbons at a low temperature (443 K) over a Pt/zeolite catalyst without hydrogen or other expensive reagents was investigated. Pt supported on NH4+-form ultra-stable Y-type (NH4-USY) zeolite catalyst, which showed the highest activity among the tested Pt/zeolite catalysts, has appropriate acidity and a suitable active Pt site. The C3+C4 hydrocarbon yield reached 14.5 C-% during the reaction over the Pt/NH4-USY catalyst at 443 K after 72 h of the reaction. Results showed that the acid strength of the zeolite support was an important factor affecting the cellulose decomposition activity. Because of their structural sensitivity, Pt/zeolite catalysts with Pt particles larger than 5 nm, including Pt/NH4-USY catalyst, showed higher TOF values than catalysts with Pt particles smaller than 5 nm.

    DOI

  • Non-oxidative ethane dehydroaromatization on Co/H-ZSM-5 catalyst

    Hikaru Saito, Ryota Terunuma, Kiria Kojima, Tomohiro Yabe, Shuhei Ogo, Haruaki Hirayama, Yukio Tanaka, Yasushi Sekine

    Chemistry Letters   46 ( 11 ) 1646 - 1649  2017  [Refereed]

     View Summary

    © 2017 The Chemical Society of Japan. Non-oxidative ethane dehydroaromatization to form aromatic hydrocarbons was investigated over various metal supported on H-ZSM-5 catalysts. Co/H-ZSM-5 prepared using an ion-exchange (IE) method exhibited high catalytic performance with a small amount of carbon deposition. Results obtained from temperature-programmed reduction and X-ray absorption fine structure spectroscopy indicate that stable Co2+ cations exist on Co/H-ZSM-5 IE during the reaction. Co2+ cations efficiently activate ethane without coke formation.

    DOI

  • Surface Protonics Promotes Catalysis

    R. Manabe, S. Okada, R. Inagaki, K. Oshima, S. Ogo, Y. Sekine

    Scientific Reports   6  2016.12  [Refereed]

     View Summary

    © The Author(s) 2016. Catalytic steam reforming of methane for hydrogen production proceeds even at 473 K over 1 wt% Pd/CeO2 catalyst in an electric field, thanks to the surface protonics. Kinetic analyses demonstrated the synergetic effect between catalytic reaction and electric field, revealing strengthened water pressure dependence of the reaction rate when applying an electric field, with one-third the apparent activation energy at the lower reaction temperature range. Operando-IR measurements revealed that proton conduction via adsorbed water on the catalyst surface occurred during electric field application. Methane was activated by proton collision at the Pd-CeO2 interface, based on the inverse kinetic isotope effect. Proton conduction on the catalyst surface plays an important role in methane activation at low temperature. This report is the first describing promotion of the catalytic reaction by surface protonics.

    DOI

  • Pre-reduction and K loading effects on noble metal free Co-system catalyst for water gas shift reaction

    Tomohiro Majima, Eugene Kono, Shuhei Ogo, Yasushi Sekine

    Applied Catalysis A: General   523   92 - 96  2016.08  [Refereed]

     View Summary

    © 2016 Elsevier B.V. All rights reserved. Water gas shift (WGS) reaction over a noble metal free Co-system catalyst was investigated. Although K/Co3O4 showed no WGS activity with no pre-treatment, it showed high and stable activity after reduction by CO + H2 (syngas). Moreover, the high activity was retained even after post-treatment in water vapor. Characterization of the catalyst was conducted using XRD, XPS, and XAFS, which revealed that conducting pre-reduction, especially using CO + H2 caused the formation of Co2C, which is a potential candidate as an active site, and that K donated electrons during reduction to form stable Co2C, suppressing the formation of metallic Co. The catalyst has high competence in activity with noble metal WGS catalysts and conventional LTS catalyst, which can be a promising candidate for a WGS reaction catalyst.

    DOI

  • Low Temperature Catalytic Water Gas Shift in an Electric Field

    Yasushi Sekine, Kodai Yamagishi, Yukako Nogami, Ryo Manabe, Kazumasa Oshima, Shuhei Ogo

    Catalysis Letters   146 ( 8 ) 1423 - 1428  2016.08  [Refereed]

     View Summary

    © 2016, Springer Science+Business Media New York. Abstract: Catalytic water gas shift for hydrogen production in the temperature range of 423–873 K, was examined imposing an electric field to the catalyst bed. Reaction trends were investigated based on thermodynamic equilibrium and chemical kinetic law. Pt/La–ZrO2 was chosen as an active catalyst through our screening tests, and the effect of the electric field on the catalytic activity was investigated by changing reaction temperatures and applied electric currents. Although the reaction was ruled by thermodynamic equilibrium at high temperatures, drastic promotion of the reaction by applying the electric field was observed at low temperatures in a kinetic region. Drastic decrease of apparent activation energy for WGS was observed by imposing the electric field to the catalyst bed. Various isotopic transient tests revealed that the reaction mechanism changed by the application of electric field, and redox mechanism using surface lattice oxygen played an important role in case of the catalytic WGS in the electric field. Graphical Abstract: [Figure not available: see fulltext.]

    DOI

  • Highly active and stable Co/La<inf>0.7</inf>Sr<inf>0.3</inf>AlO<inf>3-δ</inf> catalyst for steam reforming of toluene

    Kent Takise, Takuma Higo, Daiki Mukai, Shuhei Ogo, Yukihiro Sugiura, Yasushi Sekine

    Catalysis Today   265   111 - 117  2016.05  [Refereed]

     View Summary

    © 2015 Elsevier B.V. All rights reserved. We investigated steam reforming of toluene as a model compound of aromatic hydrocarbons included in biomass tar over Co supported La0.7Sr0.3AlO3-δ (LSAO), perovskite oxide. Ni-supported LSAO catalyst has shown high activity and coke resistance from the redox property of lattice oxygen in/on the LSAO support. Co is known as an active metal for this reaction, so Co/LSAO catalyst was investigated in this work. Co/LSAO catalyst, which showed high steady-state activity and stability, was characterized using H218O isotopic transient response tests, STEM, FT-IR, Arrhenius plot and partial pressure dependence to elucidate high and stable catalytic activity. In situ FT-IR measurements revealed that reaction intermediates on Co/LSAO desorbed at 873 K or lower temperatures. Although redox property of lattice oxygen did not change at around 848 K based on isotopic transient tests, the Arrhenius plots indicate that the rate-determining step changed at around 848 K because of reaction intermediate decomposition desorption. Fast reaction and desorption of absorbed intermediates on Co/LSAO enable catalytic stability during toluene steam reforming.

    DOI

  • Low-temperature catalytic oxidative coupling of methane in an electric field over a Ce-W-O catalyst system

    Kei Sugiura, Shuhei Ogo, Kousei Iwasaki, Tomohiro Yabe, Yasushi Sekine

    Scientific Reports   6   25154  2016.04  [Refereed]

     View Summary

    We examined oxidative coupling of methane (OCM) over various Ce-W-O catalysts at 423 K in an electric field. Ce2 (WO4)3/CeO2 catalyst showed high OCM activity. In a periodic operation test over Ce2 (WO4)3/CeO2 catalyst, C 2 selectivity exceeded 60% during three redox cycles. However, Ce2 (WO4)3/CeO2 catalyst without the electric field showed low activity, even at 1073 K: CH 4 Conv., 6.0%; C 2 Sel., 2.1%. A synergetic effect between the Ce2 (WO4)3 structure and electric field created the reactive oxygen species for selective oxidation of methane. Results of XAFS, in-situ Raman and periodic operation tests demonstrated that OCM occurred as the lattice oxygen in Ce2 (WO4)3 (short W-O bonds in distorted WO 4 unit) was consumed. The consumed oxygen was reproduced by a redox mechanism in the electric field.

    DOI

  • 電場中でメタン酸化カップリングに高い活性を示すセリウムタングステート触媒の微細構造と電場の効果

    小河脩平, 杉浦 圭, 岩崎晃聖, 矢部智宏, 関根 泰

    触媒   58 ( B ) 57 - 59  2016.03

  • Low temperature catalytic steam reforming of ethanol over Pt catalyst

    Tsunashima Naoya, Sakurai Saori, Ogo Shuhei, Sekine Yasushi

    Proceeding of Annual/Fall Meetings of the Japan Petroleum Institute   2016   36 - 36  2016

    DOI CiNii

  • Selective adsorption of toluene over La-oxide for hydrogen carrier

    Suzuki Tomohiro, Shiono Keiri, Ogo Shuhei, Sekine Yasushi

    Proceeding of Annual/Fall Meetings of the Japan Petroleum Institute   2016   49 - 49  2016

    DOI CiNii

  • Tri-reforming of methane at low temperature in an electric field

    Oguri Tasuku, Sugiura Kei, Ogo Shuhei, Sekine Yasushi

    Proceeding of Annual/Fall Meetings of the Japan Petroleum Institute   2016   54 - 54  2016

    DOI CiNii

  • Effect of hydrocarbon structure on steam reforming over Ni/perovskite catalyst

    Higo Takuma, Hashimoto Takashi, Mukai Daiki, Nagatake Satoshi, Ogo Shuhei, Sugiura Yukihiro, Sekine Yasushi

    Proceeding of Annual/Fall Meetings of the Japan Petroleum Institute   2016   50 - 50  2016

    DOI CiNii

  • Effect of Mn addition on the catalytic dehydrogenation of methyl-cyclohexane

    Nakano Atsushi, Nagatake Satoshi, Higo Takuma, Sugiura Yukihiro, Iki Hideshi, Ogo Shuhei, Sekine Yasushi

    Proceeding of Annual/Fall Meetings of the Japan Petroleum Institute   2016   48 - 48  2016

    DOI CiNii

  • Water gas shift reaction over cobalt catalyst

    Majima Tomohiro, Ogo Shuhei, Sekine Yasushi

    Proceeding of Annual/Fall Meetings of the Japan Petroleum Institute   2016   53 - 53  2016

    DOI CiNii

  • Catalytic effect of reactor surface on ethane cracker

    Maeda Shun, Ogo Shuhei, Otsubo Kenji, Sekine Yasushi

    Proceeding of Annual/Fall Meetings of the Japan Petroleum Institute   2016   10 - 10  2016

    DOI CiNii

  • Suppression of combustion for exhaust gas and methane reforming by Mg addition

    Oguri Tasuku, Sugiura Kei, Ogo Shuhei, Sekine Yasushi

    Proceeding of Annual/Fall Meetings of the Japan Petroleum Institute   2016   36 - 36  2016

    DOI CiNii

  • Influence of oxygen redox property and anchoring behavior on Co supported catalyst during toluene steam reforming reaction

    Takise Kent, Manabe Shota, Muraguchi Keisuke, Higo Takuma, Ogo Shuhei, Sekine Yasushi

    Proceeding of Annual/Fall Meetings of the Japan Petroleum Institute   2016   50 - 50  2016

     View Summary

    Activity tests and some characterizations were conducted on Co supported catalyst during and after toluene steam reforming. FE-TEM measurements and XPS measurements revealed that an anchoring behavior between Co metals and a support oxygen was confirmed only when La ion and lattice defection coexist in/on the support oxygen. Also, a redox property of support is significant for activating steam and toluene according to SSITKA (Steady State Isotopic Transient Kinetic Analysis) and XPS measurements. Compatibility of the anchoring behavior and the redox property enabled 10wt%Co/La0.7Sr0.3AlO2.85 to indicate highest activity during toluene steam reforming.<br>

    DOI CiNii

  • Low-temperature catalytic oxidative coupling of methane using carbon dioxide in an electric field over La perovskite oxide catalysts

    Yabe Tomohiro, Kamite Yukiko, Sugiura Kei, Ogo Shuhei, Sekine Yasushi

    Proceeding of Annual/Fall Meetings of the Japan Petroleum Institute   2016   49 - 49  2016

     View Summary

    Catalytic oxidative coupling of methane using carbon dioxide in an electric field was conducted at lower temperature, 423 K. As a result, the highest OCM activity, C2 yield of 7.4 %, was obtained even at 348 K, that value was higher than those of other earlier reports. Methane activation was promoted by increasing the imposed current and/or imposed power. To show the same catalytic activity by heating the catalyst, very high temperature was required, even at 1323 K in the conventional catalytic reaction. In addition, the incorporation of Ca atoms in the LaAlO3 structure, stabilizing Ca atoms, was important for the formation of C2 hydrocarbons.

    DOI CiNii

  • Development of novel catalytic dehydrogenation system for new ethane cracker

    Maeda Shun, Miyamoto Yuji, Ogo Shuhei, Hashimoto Kunihide, Sekine Yasushi

    Proceeding of Annual/Fall Meetings of the Japan Petroleum Institute   2016   35 - 35  2016

    DOI CiNii

  • Low temperature NOx reduction over Pd/perovskite catalyst

    Tsuchiya Hiroto, Higo Takuma, Ueno Kohei, Ogo Shuhei, Sekine Yasushi

    Proceeding of Annual/Fall Meetings of the Japan Petroleum Institute   2016   37 - 37  2016

    DOI CiNii

  • Oxidative coupling of methane in an electri field over Ce-W-O oxide catalyst

    Sato Ayaka, Iwasaki Kosei, Sugiura Kei, Ogo Shuhei, Sekine Yasushi

    Proceeding of Annual/Fall Meetings of the Japan Petroleum Institute   2016   119 - 119  2016

    DOI CiNii

  • Dehydrogenative aromatization of ethane over metal-supported zeolite catalyst

    Kojima Kiria, Saito Hikaru, Ogo Shuhei, Hirayama Haruaki, Tanaka Yukio, Sekine Yasushi

    Proceeding of Annual/Fall Meetings of the Japan Petroleum Institute   2016   122 - 122  2016

    DOI CiNii

  • Methane conversion over core-shell catalyst in an electric field

    Torimoto Maki, Mitarai Kenta, Ogo Shuhei, Sekine Yasushi

    Proceeding of Annual/Fall Meetings of the Japan Petroleum Institute   2016   120 - 120  2016

    DOI CiNii

  • Hydrogen production by water-splitting by catalytic reaction in an electric field

    Ogino Kentaro, Ogo Shuhei, Kondo Wakichi, Takeyama Masaki, Kojima Kunihiro, Sekine Yasushi

    Proceeding of Annual/Fall Meetings of the Japan Petroleum Institute   2016   19 - 19  2016

    DOI CiNii

  • Development of La-oxide for selective adsorption of toluene using as a hydrogen carrier purification

    Suzuki Tomohihro, Shiono Keiri, Ogo Shuhei, Sekine Yasushi

    Proceeding of Annual/Fall Meetings of the Japan Petroleum Institute   2016   17 - 17  2016

    DOI CiNii

  • Effect of electric field on catalytic methane steam refomring

    Inagaki Reona, Okada Shigeki, Manabe Ryo, Ogo Shuhei, Sekine Yasushi

    Proceeding of Annual/Fall Meetings of the Japan Petroleum Institute   2016   6 - 6  2016

    DOI CiNii

  • Effect of Pt-supported zeolite catalyst preparation on catalytic conversion of cellulose to C3-C4 hydrocarbons

    Okuno Yutaro, Sekine Hikaru, Onda Ayumu, Ogo Shuhei, Sekine Yasushi

    Proceeding of Annual/Fall Meetings of the Japan Petroleum Institute   2016   129 - 129  2016

    DOI CiNii

  • 木質系バイオマスの水熱環境での触媒転換による有用化合物の合成

    小河脩平, 関根 輝, 関根 泰

    日本エネルギー学会誌   95   510 - 514  2016

  • 電場印加触媒反応によるメタンと二酸化炭素からのC2炭化水素の合成

    矢部智宏, 小河脩平, 関根 泰

    二酸化炭素を用いた化学品製造技術     15 - 22  2016

  • 水素製造技術の現状と今後

    関根 泰

    ケミカルエンジニヤリング   5   309 - 313  2016

  • 再生可能資源からの水素製造

    比護拓馬, 小河脩平, 関根 泰

    再生可能エネルギーを用いた水素製造    2016

  • メタン転換・C1化学におけるゼオライト

    矢部智宏, 斎藤 晃, 小河脩平, 関根 泰

    ナノ空間材料     288 - 295  2016

  • One pot direct catalytic conversion of cellulose to C<inf>3</inf> and C<inf>4</inf> hydrocarbons using Pt/H-USY zeolite catalyst at low temperature

    Shuhei Ogo, Taku Nishio, Hikaru Sekine, Ayumu Onda, Yasushi Sekine

    Fuel Processing Technology   141 ( 1 ) 123 - 129  2016.01  [Refereed]

     View Summary

    © 2015 Elsevier B.V. All rights reserved. One-pot direct catalytic conversion of cellulose to light hydrocarbon at low temperature (443 K) in the presence of Pt-zeolite catalysts and water was investigated. Results revealed that Pt supported on H+-form ultra stable Y-type (H-USY) zeolite catalyst (Pt/H-USY) enabled direct conversion of cellulose into C3 and C4 hydrocarbons without hydrogen and other expensive reagents. This production trend is attributable to the bifunctional catalysis of supported Pt and acid site in H-USY zeolite, which has a large pore system and effective acidity. Results revealed that the pre-treatment of catalyst was important for selective olefin production. Air-oxidized Pt/H-USY catalyst showed higher olefin selectivity than the catalyst reduced with hydrogen. The Pt/H-USY catalysts showed high stability under the reaction condition. Results suggest that C5 sugars were the reaction intermediate for the C3 hydrocarbons, and C6 sugars were the intermediate for C4 hydrocarbon formation from cellulose over Pt/H-USY catalysts.

    DOI

  • Ni/ペロブスカイト触媒を用いた芳香族の水蒸気改質による水素製造

    比護拓馬, 関根 泰

    ペトロテック   39 ( 9 ) 25 - 29  2016

  • Hydrogen production by steam reforming of ethanol over Pt/CeO<inf>2</inf> catalyst in electric field at low temperature

    Saori Sakurai, Shuhei Ogo, Yasushi Sekine

    Journal of the Japan Petroleum Institute   59 ( 5 ) 174 - 183  2016  [Refereed]

     View Summary

    Catalytic ethanol steam reforming over Pt/CeO2 catalyst in an electric field at low temperature and the effect of the electric field and controlling factors for the activity and selectivity were investigated. With the electric field ethanol steam reforming proceeded at temperatures as low as 423 K at which the conventional catalytic reaction hardly proceeded. Conversion of ethanol and H2 yield significantly increased with the electric field and apparent activation energies for ethanol dehydrogenation acetaldehyde decomposition and acetaldehyde steam reforming were lowered by the electric field. In-situ DRIFTS measurements revealed that the adsorbed ethanol formed reactive acetate species with the electric field even at low temperature which improved H2 selectivity.

    DOI

  • Free-surfactant synthesis of graphene-layered carbon composite and its utilization for electrocatalysis

    Kei Mukawa, Naganobu Oyama, Toshitaka Shinmi, Yasushi Sekine

    Bulletin of the Chemical Society of Japan   89 ( 8 ) 892 - 898  2016  [Refereed]

     View Summary

    © 2016 The Chemical Society of Japan. We synthesized a characteristic graphene-layered carbon particle composite using pyrolysis of hydrocarbon in an electric field and consecutive activation treatment under CO2 atmosphere. TEM, N2 adsorption isotherm, Raman spectroscopy, and XPS revealed structural features of this unique composite. Graphenes and carbon particles in the resultant composite are combined homogeneously in nanoscale with a mesoscale structure and with high carbon purity. When Pt nanoparticles are loaded on the composite, they show high performance as an electrocatalyst because of their higher electrochemical active surface area and higher durability against the sintering of Pt nanoparticles. Resulting material is a multifunctional composite by virtue of its nanostructural features.

    DOI

  • Dehydrogenation of Methylcyclohexane over Pt/TiO<inf>2</inf> Catalyst

    Satoshi Nagatake, Takuma Higo, Shuhei Ogo, Yukihiro Sugiura, Ryo Watanabe, Choji Fukuhara, Yasushi Sekine

    Catalysis Letters   146 ( 1 ) 54 - 60  2016.01  [Refereed]

     View Summary

    © 2015 Springer Science+Business Media New York. Methylcyclohexane (MCH) is expected as a hydrogen carrier. Dehydrogenation of MCH was conducted over supported Pt catalysts at 623 K. Pt/TiO2 showed high stability for dehydrogenation and good resistance for coke formation. The partial pressure dependence of MCH, toluene, and H2 was investigated for Pt/TiO2 and Pt/Al2O3 catalysts, which showed different tendencies for toluene partial pressure. The reaction order of toluene partial pressure for Pt/TiO2 was almost zero, but that for Pt/Al2O3 was a negative value. Toluene inhibited the Pt/Al2O3 catalytic activity, but that of Pt/TiO2 was unaffected. The SMSI effect was confirmed on Pt/TiO2 by CO chemisorption measurement. Pt on TiO2 became an electron-rich state compared to Pt0 because of the electron donation from TiOx, and the toluene adsorption to Pt on TiO2 was weakened.

    DOI

  • Zeolite Membrane for Dehydration of Isopropylalcohol-Water Mixture by Vapor Permeation

    Ken Ichi Sawamura, Taisuke Furuhata, Yasushi Sekine, Eiichi Kikuchi, Bharathi Subramanian, Masahiko Matsukata

    ACS Applied Materials and Interfaces   7 ( 25 ) 13728 - 13730  2015.07  [Refereed]

     View Summary

    © 2015 American Chemical Society. Highly stable FAU-type zeolite membrane for the separation of isopropanol (IPA)-water mixture by pervaporation is described. FAU membrane showed high water permselectivity and permeance. Comparison of FAU membrane with a conventional LTA-type zeolite membrane revealed superior stability of FAU zeolite membrane in a mixture containing a large water content. (Figure Presented).

    DOI

  • Synthesis of stable anisotropic carbon particle aggregates covered by surface nano-graphitic sheets

    Kei Mukawa, Naganobu Oyama, Hiroaki Ando, Takashi Sugiyama, Shuhei Ogo, Yasushi Sekine

    Carbon   88 ( 88 ) 33 - 41  2015.07  [Refereed]

     View Summary

    © 2015 Elsevier Ltd. All rights reserved. Abstract For this study, pyrolytic carbon particles were synthesized in a pyrolytic reactor in which a moderate electric field by DC power was generated between two electrodes at the center of the pyrolysis zone at 1573 K. The resulting carbon particles, which were collected on the top of the electrode, were analyzed to assess their microstructure and nanostructure using TEM observation, Raman spectroscopy, X-ray diffraction measurement, and light scattering size distribution measurements. Results showed that the resulting carbon particles formed a characteristic structure; the anisotropic chain-like configuration (fractal dimension, Df = 1.65 ± 0.02), with graphitic thin nanolayers having high crystallinity covering the surface of these aggregates. Morphological analysis with the concept of the fractal dimension of the aggregate indicates that the electric field regulates the aggregate morphology. The other experiment which the carbon source was fed onto prefabricated pyrolysis carbon particles under 1537 K showed that surface graphitic layers on the aggregate was derived from gas phase carbon sources, not from graphitizing of the surface structure of carbon particles. The ultrasonication of carbon particles with/without surface graphitic layers in the ethanol solution also confirmed that the specific role of the layers that supports stabilization of the aggregate configuration.

    DOI

  • Steam reforming of ethanol over K promoted Co catalyst

    Shuhei Ogo, Takuya Shimizu, Yusaku Nakazawa, Kei Mukawa, Daiki Mukai, Yasushi Sekine

    Applied Catalysis A: General   495 ( 495 ) 30 - 38  2015.04  [Refereed]

     View Summary

    © 2015 Elsevier B.V. All rights reserved. We investigated the catalytic activity of Co/K/α-Al<inf>2</inf>O<inf>3</inf> with various potassium (K) loadings for ethanol steam reforming. The promotion effect of K loading and the role of K in Co/K/α-Al<inf>2</inf>O<inf>3</inf> were investigated using TEM-EDX, H<inf>2</inf>-TPR, XAFS, XPS, and IR measurements. Results show that loading of 1-2 wt% K on Co/α-Al<inf>2</inf>O<inf>3</inf> was effective for improving catalytic activity, selectivity to hydrogen and suppressing by-product (CH<inf>4</inf>, C<inf>2</inf>H<inf>4</inf>, and coke) formations. Measurements by H<inf>2</inf>-TPR and XAFS showed that the reducibility of the supported Co species decreased by K loading. TEM measurements revealed that the Co0-CoO core-shell structure was formed over Co/K/α-Al<inf>2</inf>O<inf>3</inf> during ethanol steam reforming at 823 K, suggesting that the oxidized Co species (CoO) is a highly active species in ethanol steam reforming. In situ IR measurements revealed that the adsorbed ethanol forms stable acetate species by K loading, which improves hydrogen selectivity.

    DOI

  • No.21 Catalytic conversion of cellulose biomass over Pt supported catalyst into valuable chemicals

    OGO Shuhei, SEKINE Hikaru, MUKAWA Kei, OYAMA Naganobu, SHINMI Toshitaka, ONDA Ayumu, SEKINE Yasushi

    Proceedings of Conference on Coal Science   52   42 - 43  2015

     View Summary

    One-pot direct catalytic conversion of cellulose to light hydrocarbon at low temperature (443 K) in the presence of Pt-supported catalysts and water was investigated. Pt supported on H^+-form ultra-stable Y-type (H-USY) zeolite catalyst (Pt/H-USY) enabled direct conversion of cellulose into C_3 and C_4 hydrocarbons without hydrogen and other expensive reagents. Results revealed that the pre-treatment of catalyst was important for selective olefin production. Air-oxidized Pt/H-USY catalyst showed higher olefin selectivity than the catalyst reduced with hydrogen. The Pt/H-USY catalysts showed high stability under the reaction condition.

    DOI CiNii

  • Effect of electric field on ethanol steam reforming over Pt supported catalyst at low temperature

    Ogo Shuhei, Sakurai Saori, Sekine Yasushi

    Proceeding of Annual/Fall Meetings of the Japan Petroleum Institute   2015   114 - 114  2015

    DOI CiNii

  • In-situ IR Study of Methane Steam Reforming with an Electric Field

    Okada Shigeki, Manabe Ryo, Sasaki Yusuke, Oshima Kazumasa, Ogo Shuhei, Sekine Yasushi

    Proceeding of Annual/Fall Meetings of the Japan Petroleum Institute   2015   34 - 34  2015

    DOI CiNii

  • Ethanol steam reforming over metal supported apatite catalyst at low temperature.

    Maeda Shun, Miyanaga Mitsumasa, Shimizu Takuya, Ogo Shuhei, Sekine Yasushi

    Proceeding of Annual/Fall Meetings of the Japan Petroleum Institute   2015   33 - 33  2015

    DOI CiNii

  • Catalytic steam reforming of toluene over Co/Perovskite -2-

    Manabe Shota, Takise Kent, Higo Takuma, Mukai Daiki, Ogo Shuhei, Sugiura Yukihiro, Sekine Yasushi

    Proceeding of Annual/Fall Meetings of the Japan Petroleum Institute   2015   35 - 35  2015

    DOI CiNii

  • Effect of electric field on water gas shift

    Yamagishi Kodai, Ikeda Tomohiro, Oshima Kazumasa, Ogo Shuhei, Sekine Yasushi

    Proceeding of Annual/Fall Meetings of the Japan Petroleum Institute   2015   135 - 135  2015

    DOI CiNii

  • Steam reforming of toluene over Co/perovskite No.1

    Takise Kent, Higo Takuma, Manabe Shota, Mukai Daiki, Ogo Shuhei, Sugiura Yukihiro, Sekine Yasushi

    Proceeding of Annual/Fall Meetings of the Japan Petroleum Institute   2015   34 - 34  2015

    DOI CiNii

  • Direct catalytic conversion of cellulose into propylene and butene over Pt/zeolite catalyst

    Sekine Hikaru, Onda Ayumu, Ogo Shuhei, Sekine Yasushi

    Proceeding of Annual/Fall Meetings of the Japan Petroleum Institute   2015   152 - 152  2015

    DOI CiNii

  • Direct catalytic conversion of cellulose into propylene and butene over Pt/H-USY zeolite catalyst

    Sekine Hikaru, Nishio Taku, Onda Ayumu, Ogo Shuhei, Sekine Yasushi

    Proceeding of Annual/Fall Meetings of the Japan Petroleum Institute   2015   24 - 24  2015

    DOI CiNii

  • Effect of potassium loading on water-gas shift reaction over K/Co3O4 catalyst

    Majima Tomohiro, Kono Eugene, Ogo Shuhei, Sekine Yasushi

    Proceeding of Annual/Fall Meetings of the Japan Petroleum Institute   2015   35 - 35  2015

    DOI CiNii

  • Structure of catalyst for highly active methane oxidative coupling in an electric field

    Iwasaki Kosei, Sugiura Kei, Yabe Tomohiro, Ogo Shuhei, Sekine Yasushi

    Proceeding of Annual/Fall Meetings of the Japan Petroleum Institute   2015   73 - 73  2015

    DOI CiNii

  • Oxidation coupling of methane using CO2 as an oxidizing agent over La0.7Ca0.3AlO3-&delta; catalyst in an electric field

    Kamite Yukiko, Yabe Tomohiro, Sugiura Kei, Ogo Shuhei, Sekine Yasushi

    Proceeding of Annual/Fall Meetings of the Japan Petroleum Institute   2015   70 - 70  2015

    DOI CiNii

  • Catalytic steam reforming of n -butane in an electric field

    Iwano Shin, Morikawa Shinya, Ogo Shuhei, Sekine Yasushi

    Proceeding of Annual/Fall Meetings of the Japan Petroleum Institute   2015   39 - 39  2015

    DOI CiNii

  • Direct conversion of glucose to light olefin using Pt catalyst supported on nano structured graphene

    Shinmi Toshitaka, Mukawa Kei, Oyama Naganobu, Sekine Hikaru, Onda Ayumu, Ogo Shuhei, Sekine Yasushi

    Proceeding of Annual/Fall Meetings of the Japan Petroleum Institute   2015   182 - 182  2015

    DOI CiNii

  • Development of novel catalyst for dehydrogenation of methylcyclohexane

    Nakano Atsushi, Nagatake Satoshi, Higo Takuma, Nagatsuka Tomomi, Sugiura Yukihiro, Iki Hideshi, Ogo Shuhei, Sekine Yasushi

    Proceeding of Annual/Fall Meetings of the Japan Petroleum Institute   2015   94 - 94  2015

    DOI CiNii

  • Oxidative coupling of methane in an electric field over supported poly(oxotungstate) catalysts

    Iwasaki Kosei, Sugiura Kei, Yabe Tomohiro, Ogo Shuhei, Sekine Yasushi

    Proceeding of Annual/Fall Meetings of the Japan Petroleum Institute   2015   42 - 42  2015

    DOI CiNii

  • Steam reforming of ethanol in an electric field at low temperature

    Ogo Shuhei, Sakurai Saori, Sekine Yasushi

    Proceeding of Annual/Fall Meetings of the Japan Petroleum Institute   2015   38 - 38  2015

    DOI CiNii

  • The effect of Ba addition to Ni/LaAlO3 catalyst for steam reforming of toluene

    Saito Hikaru, Higo Takuma, Sugiura Yukihiro, Kubo Koichi, Ogo Shuhei, Sekine Yasushi

    Proceeding of Annual/Fall Meetings of the Japan Petroleum Institute   2015   39 - 39  2015

    DOI CiNii

  • Analysis of reaction mechanism for methane dry reforming over Ni/La-ZrO2 catalyst in an electric field

    Mitarai Kenta, Oshima Kazumasa, Yabe Tomohiro, Ogo Shuhei, Sekine Yasushi

    Proceeding of Annual/Fall Meetings of the Japan Petroleum Institute   2015   37 - 37  2015

    DOI CiNii

  • コバルト触媒を用いたバイオエタノールの水蒸気改質による水素製造

    小河脩平, 関根泰

    月刊ケミカルエンジニアリング   60 ( 3 ) 1 - 7  2015

  • メタンの酸化的カップリング

    矢部智宏, 小河脩平, 関根 泰

    ファインケミカル   44 ( 8 ) 14 - 17  2015

  • 資源エネルギーと触媒技術の展望

    関根 泰

    触媒技術の動向と展望2015     256 - 259  2015

  • メタンの酸化的カップリング

    矢部智宏, 小河脩平, 関根 泰

    ファインケミカル   8 ( 44 ) 5 - 9  2015

  • コバルト触媒を用いたバイオエタノールの水蒸気改質による水素製造

    小河脩平, 関根 泰

    ケミカルエンジニアリング   ( 3 ) 165 - 171  2015

  • Pd/K/Co-oxide catalyst for water gas shift

    Eugene Kono, Sakurako Tamura, Keisuke Yamamuro, Shuhei Ogo, Yasushi Sekine

    Applied Catalysis A: General   489 ( 489 ) 247 - 254  2015.01  [Refereed]

     View Summary

    © 2014 Elsevier B.V. All rights reserved. Various Co3 O4 catalysts were investigated for the water gas shift (WGS) reaction for hydrogen production. Although the catalyst supporting only palladium (Pd/Co3 O4) showed low catalytic activity and higher selectivity to methanation, Pd/K/Co3 O4catalyst, with loading of potassium exceeding 0.78 wt%, showed high catalytic activity for the WGS reaction. Catalysts on which Pd and K exist closely showed high activity, as confirmed using various preparation methods. Results of XPS measurements for Pd/K/Co3 O4 revealed that supported potassium donated electrons to Pd and Co. The state of CO adsorption species was affected by the potassium loading, resulting in high catalytic activity for the Pd/K/Co3 O4 catalyst. These effects gave the Pd/K/Co3 O4 catalyst high catalytic activity for the WGS reaction. That reaction over Pd/K/Co3 O4 proceeds via surface cobalt carbonyl and then formate intermediates, as revealed by the TG and isotope exchange measurements using H218O and DRIFT.

    DOI

  • Partial Oxidation of Methane over Modified Ni/α-Al2O3 Catalyst at Low Temperature

    Daiki Mukai, Yuji Kondo, Toshinari Eda, Shuhei Ogo, Yasushi Sekine

    Journal of the Japan Petroleum Institute   58 ( 1 ) 46 - 54  2015.01  [Refereed]

    DOI

  • Effect of hydrocarbon structure on steam reforming over Ni/perovskite catalyst

    Takuma Higo, Takashi Hashimoto, Daiki Mukai, Satoshi Nagatake, Shuhei Ogo, Yukihiro Sugiura, Yasushi Sekine

    Journal of the Japan Petroleum Institute   58 ( 2 ) 86 - 96  2015  [Refereed]

     View Summary

    © 2015, Japan Petroleum Institute. All rights reserved. Ni/perovskite-type oxide catalyst (Ni/La<inf>0.7</inf>Sr<inf>0.3</inf>AlO<inf>2.85</inf>: LSAO) shows high catalytic activity and low carbon formation during the steam reforming of aromatic hydrocarbons because of the high mobility of lattice oxygen in the support. The reaction mechanisms of the catalyst were investigated by characterizations and catalytic activity tests for steam reforming of various hydrocarbons including toluene, methylcyclohexane, and n-heptane. The catalytic performance was affected by the reactant structure, as revealed by Arrhenius plots and FT-IR analyses. Adsorption state and stability of reaction intermediates were very important factors in the catalytic activity for steam reforming.

    DOI

  • Effect of catalyst structure on steam reforming of toluene over Ni/La<inf>0.7</inf>Sr<inf>0.3</inf>AlO<inf>3-δ</inf> catalyst

    Kento Takise, Masaya Imori, Daiki Mukai, Shuhei Ogo, Yukihiro Sugiura, Yasushi Sekine

    Applied Catalysis A: General   489 ( 489 ) 155 - 161  2015.01  [Refereed]

     View Summary

    © 2014 Elsevier B.V. All rights reserved. We investigated steam reforming of toluene as a biomass tar model on Ni/La0.7Sr0.3AlO3-δ, which has high activity and low carbon deposition for hydrogen production. Carbon deposition was suppressed by the oxidation of surface carbon species with lattice oxygen on support. The effects of Ni particle size and support surface area on catalytic features were evaluated by varying the calcination temperature of supported Ni and perovskite support independently. Activity tests, isotopic transient response tests, and characterization were performed to ascertain how interaction between Ni and support contributes to this reaction. Additionally, we evaluated the catalytic activity and carbon deposition per unit of Ni surface and perimeter. The lattice oxygen release rate depends on the specific surface area of the support, Ni-support interface, and catalyst structure. High surface area of the support accelerates the exchange of lattice oxygen through the redox cycle during steam reforming. Furthermore, the larger interface between Ni and support enables rapid lattice oxygen release. When the lattice oxygen release rate was higher, the catalytic activity was higher and carbon deposition was lower for each catalyst. These results confirm that lattice oxygen plays an important role in the activation of toluene and removal of carbon deposition on supported Ni.

    DOI

  • Effect of ozone addition to lean NO<inf>x</inf>trap method using plasma-catalyst system

    Masato Nagata, Yasunari Hanaki, Atsushi Ikeda, Yasushi Sekine

    Plasma Chemistry and Plasma Processing   34 ( 6 ) 1303 - 1315  2014.11  [Refereed]

     View Summary

    © 2014 Springer Science+Business Media New York. Although diesel vehicles have high energy efficiency, the removal of emitted NOxat low temperature persists as an important issue. This report presents an examination of low-temperature NOxremoval using ozone injection and a plasma-lean NOxtrap (LNT) catalyst system. Ozone is readily producible by a dielectric barrier discharge reactor using oxygen in air, and its injection to emitted NO enables oxidation to NO2even at low temperatures. Results show that synergetic effects of ozone injection and plasma-LNT catalyst system enable low-temperature NOxremoval.

    DOI

  • Low temperature catalytic reverse water gas shift reaction assisted by an electric field

    Kazumasa Oshima, Tatsuya Shinagawa, Yukako Nogami, Ryo Manabe, Shuhei Ogo, Yasushi Sekine

    Catalysis Today   232 ( 232 ) 27 - 32  2014.09  [Refereed]

     View Summary

    Catalytic reverse water gas shift reaction was conducted in an electric field (denoted as E-RWGS) over various catalysts at low temperature as 423 K. A platinum catalyst supported on lanthanum doped zirconia (Pt/La-ZrO2) showed the highest yield (ca. 40%) for the E-RWGS reaction even at such low temperature condition. In contrast to a bare oxide catalyst, metal loading catalysts showed higher activities and efficiencies for the reaction. Roles of the impregnated platinum and doped lanthanum on the catalytic activity were investigated, and we found that loaded platinum worked as an active site for the E-RWGS reaction, and La doping stabilized the structure of ZrO2. The effect of the electric field was discussed based on thermodynamic evaluation and experimental results. © 2013 Elsevier B.V. All rights reserved.

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  • Physicochemical characterization of highly dispersed platinum and chromium on zeolite beta

    Yoshiyuki Izutsu, Yuki Oku, Yusuke Hidaka, Naoki Kanaya, Yoshiki Nakajima, Jun Fukuroi, Kaname Yoshida, Yukichi Sasaki, Yasushi Sekine, Masahiko Matsukata

    Journal of Physical Chemistry C   118 ( 20 ) 10746 - 10753  2014.05  [Refereed]

     View Summary

    Structures of platinum and chromium supported on zeolite beta were investigated by XAFS, XPS, UV-vis, NH3-TPD, XRD, CO chemisorption, and molecular dynamics simulation. Both platinum and chromium were uniformly dispersed in the micropore of zeolite beta. Loading of chromium helped platinum to disperse highly and stabilized in the micropore of beta. Major species of platinum on PtCr/beta after calcination at 773 K was Pt2+ forming a Pt-O bond. The Pt-O bond disappeared, and a Pt-Pt bond did not appear by reducing PtCr/beta in hydrogen, accompanying formation of Pt0. Chromium was loaded as chromate anion in the micropore of zeolite. Results of molecular dynamics simulation showed that Pt2+ associated with CrO42- in the micropore of zeolite beta was more stable than those in the absence of chromium species. We concluded that CrO 42- electrostatically stabilizes Pt2+ and inhibits migration and aggregation of platinum. © 2014 American Chemical Society.

    DOI

  • Effect of small amount of Fe addition on ethanol steam reforming over Co/Al<inf>2</inf>O<inf>3</inf> catalyst

    Yasushi Sekine, Yusaku Nakazawa, Koji Oyama, Takuya Shimizu, Shuhei Ogo

    Applied Catalysis A: General   472 ( 472 ) 113 - 122  2014.02  [Refereed]

     View Summary

    We examined the promotion effect of Fe addition and the role of Fe on Co/α-Al2O3 catalyst for ethanol steam reforming using XAFS and IR. Activity tests of Fe/Co/α-Al2O3 with various Fe loadings show the addition of 0.22 wt% iron as an appropriate amount for the promotion of ethanol steam reforming. The investigation of apparent activation energies revealed that both ethanol steam reforming and acetaldehyde steam reforming were promoted by 0.22 wt%Fe addition. XAFS analyses revealed that Co and Fe on 0.22 wt%Fe/Co/α-Al2O3 produced Co-Fe alloy with an fcc-structure. Results of in situ IR measurements showed that acetate species were stabilized on the catalyst by loading 0.22 wt%Fe, and that the catalytic activity and selectivity to hydrogen were improved by Fe addition. © 2013 Elsevier B.V. All rights reserved.

    DOI

  • Effect of Pt addition to Ni/La<inf>0.7</inf>Sr<inf>0.3</inf>AlO <inf>3-δ</inf> catalyst on steam reforming of toluene for hydrogen production

    Daiki Mukai, Yuki Murai, Takuma Higo, Shuhei Ogo, Yukihiro Sugiura, Yasushi Sekine

    Applied Catalysis A: General   471   157 - 164  2014.02  [Refereed]

     View Summary

    Pt/Ni/La0.7Sr0.3AlO3-δ (Pt/Ni/LSAO) catalyst showed high catalytic activity and low coke formation for hydrogen production by steam reforming of toluene, even without pre-reduction. STEM-EDX and XAFS analyses revealed that Pt and Ni formed adjacent or alloy structure. Electron donation from supported Pt to Ni was observed by XPS observation, and the improvement of reducibility of Ni by Pt addition was observed by H 2-TPR. Catalytic activity of the reduced Ni was brought by the PtNi interaction. The impregnation order of Pt and Ni affected the catalytic activity and the amount of coke formation due to the difference of the structure of supported metals. Dilution effects of Pt on Ni metal and the contact between Ni and LSAO support apparently affect the suppression of coke formation. © 2013 Elsevier B.V.

    DOI

  • No.28 Catalytic Conversion of Cellulose Biomass into Valuable Chemicals

    OGO Shuhei, NISHIO Taku, SEKINE Yasushi

    Proceedings of Conference on Coal Science   51   56 - 57  2014

     View Summary

    One-pot direct catalytic conversion of cellulose biomass into valuable chemicals, such as C_3 and C_4 hydrocarbons, at low temperature (443 K) in the presence of Pt/H-USY zeolite catalysts and water were investigated. Acidic properties of Pt/H-USY zeolite catalysts were characterized by NH_3-TPD, which played important roles for the Pt-supported state and the formation of C_3 and C_4 hydrocarbons. To clarify the reaction intermediate for the C_3 and C_4 hydrocarbons, catalytic conversions of various substrates were conducted. Results suggested that C_5 compounds (xylose and furfural) might be imermediates of C_3 hydrocarbon formation, while C_6 mono- and di-saccharides (cellobiose, glucose, and fructose) might be intermediates of C_4 hydrocarbon formation from cellucose over Pt/H-USY zeolite catalyst.

    DOI CiNii

  • 非在来型触媒反応での水素製造

    関根 泰

    クリーンエネルギー   ( 5 ) 41 - 46  2014

  • 電場中での天然ガスからの低温水素製造用触媒

    大島一真, 関根 泰

    触媒技術の動向と展望2014     75 - 84  2014

  • 第4編第1章 シェール革命による石油化学原料生産への影響と今後の展望

    矢部 智宏, 真鍋 亮, 関根 泰

    シェールガス〜開発・生産と石油化学〜     229 - 240  2014

  • シェールガスをはじめとする非在来型化石資源と今後のエネルギー・化学

    関根 泰

    水素エネルギーシステム   39 ( 2 ) 116 - 121  2014

  • Coking technology using heavy oil residue and hyper coal

    Yasushi Sekine, Fumitaka Sumomozawa, Takahiro Shishido

    ISIJ International   54 ( 11 ) 2446 - 2453  2014  [Refereed]

     View Summary

    © 2014 ISIJ. Oil sand bitumen and hypercoal are examined as a caking additives to the mixture of strongly coking coal and non-slightly coking coal. Samples were coked, then their strength, crystallinity of the carbon structure, and an anisotropic microstructure were measured. Oil sand bitumen addition enhanced strength, but 15% addition caused a strength decline because of the formation of large pores and cracks. Hypercoal addition increased strength with increased its content. Correlation was observed between increased strength and the crystallinity of a carbon structure or the anisotropic microstructure. Results suggest that mutual melting occurred between a coal blend and a caking additive. Then the caking additive took a carbon structure with high crystallinity by coking, achieved a function as a binder material that connects coal-particle interfaces, and ultimately enhanced strength.

    DOI

  • Low-temperature NO decomposition in humidified condition using plasma-catalyst system

    Yohei Takahara, Atsushi Ikeda, Masato Nagata, Yasushi Sekine

    Catalysis Today   211   44 - 52  2013.08  [Refereed]

     View Summary

    This study demonstrated that a plasma-catalyst system using Pt catalyst provides high performance for NO decomposition under a humidified condition. In this work, we optimized the catalyst using various supported metals, oxides, and investigated the effects of the loading amount of metal and imposed voltage of plasma for highly efficient NO conversion. Results show that Pt is the most active metal and that it promotes formation of N2 and N2O from NO, and that N2O was an intermediate of N2 formation from NO over Pt. Regarding the effect of support, Pt catalysts supported on SiO2 and Al2O3, showed higher activity. We investigated the effects of metallic surface area of Pt and imposed voltage. Results show that both the energy input and metallic surface area of Pt plays important roles for NO decomposition to N2 in the plasma-catalyst system. The maximum peak current in plasma is extremely important. © 2013 Elsevier B.V. All rights reserved.

    DOI

  • NO<inf>x</inf> Removal Using Novel Catalytic Methods

    Yasushi Sekine, Yohei Takahara, Atsushi Ikeda, Masato Nagata

    New and Future Developments in Catalysis: Catalysis for Remediation and Environmental Concerns     441 - 459  2013.07  [Refereed]

    DOI

  • Oxidation resistance of Ni/La<inf>0.7</inf>Sr<inf>0.3</inf>AlO <inf>3-δ</inf> catalyst for steam reforming of model aromatic hydrocarbon

    Yukihiro Sugiura, Daiki Mukai, Yuki Murai, Satoshi Tochiya, Yasushi Sekine

    International Journal of Hydrogen Energy   38 ( 19 ) 7822 - 7829  2013.06  [Refereed]

     View Summary

    Oxidative resistance of Ni catalysts supported on various oxides La 0.7Sr0.3AlO3-δ, LaAlO3, and α-Al2O3 were investigated for hydrogen production by steam reforming of model aromatic hydrocarbons. Ni/α-Al2O 3 lost its steam reforming activity by oxidation treatment. In contrast, Ni/La0.7Sr0.3AlO3-δ and Ni/LaAlO3 catalysts showed steam reforming activity even after the oxidation treatment. The XANES (X-ray absorption near-edge structure) spectra at Ni K-edge for Ni/La0.7Sr0.3AlO3-δ and Ni/α-Al2O3 after oxidation treatment revealed that the supported Ni on La0.7Sr0.3AlO3-δ and α-Al2O3 were oxidized completely. Although the mean particle size of Ni on Ni/α-Al2O3 increased by oxidation treatment or reduction treatment, Ni particles on Ni/La 0.7Sr0.3AlO3-δ retained the fine structure after oxidation treatment or reduction treatment. Moreover, TPR (temperature programmed reduction) and XPS (X-ray photoelectron spectroscopy) measurements for elucidating the reducibility of Ni/La0.7Sr 0.3AlO3-δ showed that the supported Ni on La 0.7Sr0.3AlO3-δ was easily reduced even after the oxidation treatment. © 2013, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights.

    DOI

  • Highly and stably dispersed Pt catalysts supported over La <inf>1-x</inf>Sr<inf>x</inf>AlO<inf>3-0.5x</inf> perovskite for oxidative methane activation and their structures

    Daiki Mukai, Yoshiyuki Izutsu, Yasushi Sekine

    Applied Catalysis A: General   458   71 - 81  2013.05  [Refereed]

     View Summary

    Catalytic activity for oxidative methane conversion (partial oxidation of methane) over Pt catalyst supported on La1-xSrxAlO 3-0.5x was investigated. Pt/La0.7Sr0.3AlO 2.85 showed higher and more stable hydrogen yield than Pt/α-Al2O3 did. Pt/La0.7Sr 0.3AlO2.85 showed higher catalytic activity for steam reform of methane even in an oxidative atmosphere, which was attributable to high Pt dispersion in the oxidative reaction atmosphere. Pt dispersion over La0.8Sr0.2AlO2.9 or La0.7Sr 0.3AlO2.85 increased concomitantly with increasing calcination temperature in air. This phenomenon was not observed by aging in He flow. From structural analyses using XRD, XPS, EXAFS, and XANES, the interaction or coordination between Pt and surface oxygen (Os) was observed. This coordination was weakened in a reductive atmosphere and regenerated in an oxidative atmosphere. This interaction or coordination between the Pt and La1-xSrxAlO3-0.5x contributed to high Pt dispersion in an oxidative atmosphere and to high catalytic activity for the partial oxidation of methane. © 2013 Elsevier B.V. All rights reserved.

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  • Synthesis and characterization of chromium-added Pt/beta zeolite and its catalytic performance for n-heptane isomerization

    Yoshiyuki Izutsu, Yuki Oku, Yusuke Hidaka, Kaname Yoshida, Yukichi Sasaki, Yasushi Sekine, Eiichi Kikuchi, Masahiko Matsukata

    Catalysis Letters   143 ( 5 ) 486 - 494  2013.05  [Refereed]

     View Summary

    Catalysis of Pt/beta zeolite catalyst modified via the addition of various elements (Ca, Cr, Mn, Fe, Co, Ni or Cu) for n-heptane skeletal isomerization was investigated at 513 K in a conventional flow reactor with a fixed catalyst bed. It was found that, among the catalysts tested, PtCr/beta was the most promising, since its use resulted in relatively high yields of multi-branched alkanes in conjunction with a very low selectivity for cracking products. Ion exchange was found to be an effective method for the addition of chromium to zeolite, compared to the evaporation to dryness process. Platinum particle sizes were observed using STEM. While particles ~10-30 nm in size were evident on the surface of Pt/beta, they were rarely observed on the PtCr/beta catalyst. It was concluded that platinum homogeneously dispersed within beta zeolite micropores resulted in the observed decreased cracking activity during n-heptane isomerization and that the addition of chromium had been effective in increasing degree of platinum dispersion. Graphical Abstract: [Figure not available: see fulltext.] © 2013 Springer Science+Business Media New York.

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  • One pot direct catalytic conversion of cellulose to hydrocarbon by decarbonation using Pt/H-beta zeolite catalyst at low temperature

    Yuki Kato, Yasushi Sekine

    Catalysis Letters   143 ( 5 ) 418 - 423  2013.05  [Refereed]

     View Summary

    We investigated one pot direct catalytic conversion of cellulose to light hydrocarbon selectively at low temperature in the presence of Pt and solid-acid zeolite catalysts. Results revealed that Pt/H-beta zeolite catalyst prepared by ion exchange enabled selective production of C3 and C4 hydrocarbons. © 2013 Springer Science+Business Media New York.

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  • Role of alkali metal in a highly active Pd/alkali/Fe<inf>2</inf>O <inf>3</inf> catalyst for water gas shift reaction

    Ryo Watanabe, Yuji Sakamoto, Keisuke Yamamuro, Sakurako Tamura, Eiichi Kikuchi, Yasushi Sekine

    Applied Catalysis A: General   457   1 - 11  2013.04  [Refereed]

     View Summary

    Pd/K/Fe2O3 catalyst shows high activity for water gas shift (WGS) reaction. The K/Pd molar ratio on the catalyst has a remarkable effect on WGS activity. The optimum K/Pd molar ratio is about 2. In this study, to clarify the role of alkali metal (potassium), WGS activities of Pd/alkali/Fe2O3 (alkali: Li, Na, K or Cs) catalysts were investigated and the reaction mechanism over the Pd/K/Fe2O 3 catalyst was examined with transient response analyses using a concentration jump method with a quadrupole mass spectrometer (Q-Mass). Results showed that the addition of alkali metals such as Na, K and Cs drastically enhanced WGS activity, except for Li-loaded catalyst. WGS reaction over the highly active Pd/K/Fe2O3 catalyst was found to proceed via reduction-oxidation (redox) using lattice oxygen. Thereby, CO was oxidized by lattice oxygen in Fe2O3. The consumed lattice oxygen was regenerated by H2O. The results of CO-TPR revealed that oxidation of CO by lattice oxygen were enhanced by K, Cs or Na addition. H2-TPR results showed that reduction of Fe2O3 was suppressed by an increment of loading amount of potassium, which brought a high stability for the WGS reaction. The result of CO/H2O-TPR showed that steam can promote the regeneration of consumed lattice oxygen. The synergistic effect brought a high release ability of lattice oxygen for CO oxidation and also high regenerating ability of consumed lattice oxygen by H2O to produce hydrogen, to the Pd/K/Fe2O3 catalyst. It enabled high catalytic performance of the Pd/K/Fe2O3 catalyst with K/Pd molar ratio of 2. © 2013 Elsevier B.V.

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  • Oxidative dehydrogenation of ethylbenzene over La<inf>0.8</inf>Ba <inf>0.2</inf>Fe<inf>0.4</inf>Mn<inf>0.6</inf>O<inf>3-δ</inf> perovskite oxide catalyst

    Kei Mukawa, Fumitaka Sumomozawa, Eiichi Kikuchi, Ryo Watanabe, Yasushi Sekine

    Applied Catalysis A: General   456   197 - 203  2013.04  [Refereed]

     View Summary

    La0.8Ba0.2Fe0.4Mn0.6O 3-δ (LBFMO) perovskite oxide has been found to be an active catalyst for oxidative dehydrogenation of ethylbenzene working with a characteristic Mars-van Krevelen redox mechanism in which steam functions as an oxidant. Results of this study showed that LBFMO oxide exhibited higher activity in the presence of both steam and gaseous oxygen compared with that of steam redox system. The reaction rate of oxidative dehydrogenation of ethylbenzene was zero-th order in oxygen partial pressure and 1.3 order in the amount of the surface lattice oxygen, which demonstrates that the reaction proceeded with redox system and the activity was determined mainly by the available amount of surface lattice oxygen. Kinetics of regeneration of the lattice oxygen from both steam and gaseous oxygen were also investigated, which confirmed that steam and gaseous oxygen mutually function as the oxidant for lattice vacancy on LBFMO. Results of thermogravimetric analysis showed that the available amount of the lattice oxygen in the presence of both steam and gaseous oxygen was 115 mmol mol-cat-1, almost twice as high as that in steam alone (63 mmol mol-cat-1). High activity in the presence of both steam and oxygen is attributable to the fact that these can simultaneously perform as the oxidant leading to a rich amount of the surface lattice oxygen of LBFMO oxide during the reaction. © 2013 Elsevier B.V. All rights reserved.

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  • Hydrogen production by water gas shift reaction over Pd-K impregnated Co oxide catalyst

    Keisuke Yamamuro, Sakurako Tamura, Ryo Watanabe, Yasushi Sekine

    Catalysis Letters   143 ( 4 ) 339 - 344  2013.04  [Refereed]

     View Summary

    Effects of K and Pd loading on Co3O4 catalyst for the water gas shift (WGS) reaction were investigated. Pd/K/Co3O 4 catalyst showed high and stable activity and high selectivity to WGS. Regarding loading amounts of Pd and K, the latter is important for WGS activity and selectivity. XRD, XAFS, and TPR measurements confirmed potassium loading benefits. Supported Pd promoted oxidation of CO with lattice oxygen. The synergetic effect of these functions of K and Pd protected high catalyst activity and stability. © 2013 Springer Science+Business Media New York.

    DOI

  • Low temperature hydrogen production by catalytic steam reforming of methane in an electric field

    Kazumasa Oshima, Tatsuya Shinagawa, Masayuki Haraguchi, Yasushi Sekine

    International Journal of Hydrogen Energy   38 ( 7 ) 3003 - 3011  2013.03  [Refereed]

     View Summary

    Catalytic steam reforming of methane in an electric field (electroreforming) at low temperatures such as 423 K was investigated. Pt catalysts supported on CeO2, CexZr1-xO 2 solid solution and a physical mixture of CeO2 and other insulators (ZrO2, Al2O3 or SiO2) were used for electroreforming. Among these catalysts, Pt catalyst supported on CexZr1-xO2 solid solution showed the highest activity for electroreforming (CH4 conv. = 40.6% at 535.1 K). Results show that the interaction among the electrons, metal loading, and catalyst support was important for high catalytic activity on the electroreforming. Catalytic activity of the electroreforming increased in direct relation to the input current. Characterizations using X-ray diffraction (XRD), temperature programmed reduction with H2 (H2-TPR), and alternate current (AC) impedance measurement show that the catalyst structure is an important factor for activity of electroreforming.

    DOI

  • Role of support lattice oxygen on steam reforming of toluene for hydrogen production over Ni/La<inf>0.7</inf>Sr<inf>0.3</inf>AlO<inf>3-δ</inf> catalyst

    D. Mukai, S. Tochiya, Y. Murai, M. Imori, T. Hashimoto, Y. Sugiura, Y. Sekine

    Applied Catalysis A: General   453   60 - 70  2013.02  [Refereed]

     View Summary

    Catalytic steam reforming of aromatic hydrocarbon using toluene as a model compound for hydrogen production over Ni catalyst supported on perovskite oxide was investigated. Ni/La0.7Sr0.3AlO3-δ catalyst showed higher activity and lower coke formation than other Ni-supported catalysts on hydrogen production by toluene steam reforming. Transient response using H218O revealed that the surface lattice oxygen of La0.7Sr0.3AlO3-δ worked as active oxygen by redox mechanism at 873 K. Coke deposited on the catalyst surface after the reaction was removed oxidatively by lattice oxygen in/on the perovskite support. The working temperature of the lattice oxygen depended on the catalyst support characteristics. Analyses of the support structure by XRD and XPS revealed that the lattice distortion and the increasing of oxygen vacancies by partial Sr substitution enhanced the redox ability of lattice oxygen. Arrhenius plots showed that the rate-determining step of the reaction changed at a certain temperature at which the lattice oxygen was able to contribute to reaction over Ni/La0.7Sr0.3AlO3-δ and Ni/LaAlO 3. The dependence of the reaction rate on the partial pressure of H2O and toluene revealed that the rate-determining step might be the formation of hydroxyl group on the support surface in a lower temperature region and the adsorption of toluene on the Ni surface in a higher temperature region. © 2012 Elsevier B.V.

    DOI

  • Steam reforming of toluene over perovskite-supported Ni catalysts

    Yasushi Sekine, Daiki Mukai, Yuki Murai, Satoshi Tochiya, Yoshiyuki Izutsu, Kei Sekiguchi, Naomi Hosomura, Hirohisa Arai, Eiichi Kikuchi, Yukihiro Sugiura

    Applied Catalysis A: General   451   160 - 167  2013.01  [Refereed]

     View Summary

    Hydrogen production by steam reforming of toluene as a model aromatic hydrocarbon has been investigated with various Ni/perovskite catalysts. Among them, Ni/LaAlO3 catalyst showed high catalytic activity. Partial substitution of the La site of LaAlO3 support with other elements (Sr, Ba or Ca) was conducted for the Ni/LaAlO3 catalyst, and substitution with 30% Sr promoted catalytic activity and selectivity to hydrogen. Optimization for the Ni loading amount over Ni/La0.7Sr 0.3AlO3-δ catalyst revealed that 5 wt% Ni/La 0.7Sr0.3AlO3-δ had the highest toluene conversion and the smallest amount of carbon deposition. To elucidate the role of doped Sr, the catalytic natures of Sr-substituted catalyst Ni/La 0.7Sr0.3AlO3-δ and Sr-supported catalyst Ni/Sr/LaAlO3 were compared. Results show that Sr-ions should be incorporated in the LaAlO3 perovskite structure to show high catalytic performance. Based on results of transient response test with H 218O on Ni/La0.7Sr0.3AlO 3-δ, Ni/Sr/LaAlO3, and Ni/LaAlO3 at reaction temperature of 873 K, the formation of 18O-products was observed only on Ni/La0.7Sr0.3AlO3-δ catalyst derived from redox between the lattice oxygen in the perovskite and water. Lattice oxygen in the La0.7Sr0.3AlO 3-δ support worked as active oxygen species to enhance its catalytic nature. © 2012 Elsevier B.V.

    DOI

  • Dehydrogenation of methylcyclohexane on perovskite oxide support catalyst

    Hashimoto Takashi, Mukai Daiki, Sugiura Yukihiro, Sekine Yasushi

    Proceeding of Annual/Fall Meetings of the Japan Petroleum Institute   2013   15 - 15  2013

    DOI CiNii

  • The optimum condition of catalyst structure at steam reforming of methane assisted by an electric field

    Nogami Yukako, Shinagawa Tatsuya, Oshima Kazumasa, Manabe Ryo, Sekine Yasushi

    Proceeding of Annual/Fall Meetings of the Japan Petroleum Institute   2013   43 - 43  2013

    DOI CiNii

  • Oxidative coupling of methane with carbon dioxide assisted by an electric field

    Yabe Tomohiro, Oshima Kazumasa, Sekine Yasushi

    Proceeding of Annual/Fall Meetings of the Japan Petroleum Institute   2013   45 - 45  2013

    DOI CiNii

  • Catalytic dry reforming of methane assisted by an electric field

    Oshima Kazumasa, Yabe Tomohiro, Shinagawa Tatsuya, Sekine Yasushi

    Proceeding of Annual/Fall Meetings of the Japan Petroleum Institute   2013   44 - 44  2013

    DOI CiNii

  • Role of support in Ni/perovskite oxide catalysts on steam reforming of aromatic hydrocarbon

    Imori Masaya, Mukai Daiki, Tochiya Satoshi, Sugiura Yukihiro, Sekine Yasushi

    Proceeding of Annual/Fall Meetings of the Japan Petroleum Institute   2013   28 - 28  2013

    DOI CiNii

  • Steam reforming of aromatic hydrocarbo over Ni/perovskite catalyst

    Sugiura Yukihiro, Mukai Daiki, Murai Yuki, Tochiya Satoshi, Imori Masaya, Hashimoto Takashi, Sekine Yasushi

    Proceeding of Annual/Fall Meetings of the Japan Petroleum Institute   2013   29 - 29  2013

    DOI CiNii

  • Steam reforming of methane at low temperature with an electric field

    Shinagawa Tatsuya, Oshima Kazumasa, Nogami Yukako, Manabe Ryo, Sekine Yasushi

    Proceeding of Annual/Fall Meetings of the Japan Petroleum Institute   2013   42 - 42  2013

    DOI CiNii

  • 非在来型触媒反応での水素製造,

    杉浦行寛, 大島一真, 向井大揮, 小河脩平, 関根 泰

    日本エネルギー学会誌   92(11)   1028 - 1033  2013

  • 天然ガスの輸送・転換・利用に関する国内外の状況俯瞰

    関根 泰, 大島一真, 向井大揮

    触媒   55 ( 3 ) 130 - 135  2013

  • 第7章 気固反応の基礎

    関根 泰

    プラズマ反応工学ハンドブック     115 - 128  2013

  • 第13章 メタンの酸化カップリングによるC2炭化水素合成

    関根 泰, 大島一真, 小河脩平

    シェールガスの開発と化学プロセス     126 - 134  2013

  • プラズマ・電場中での触媒反応における触媒特性の交流インピーダンス測定法による評価

    大島一真, 田中芳貴, 品川竜也, 関根 泰

    静電気学会誌   37 ( 1 ) 8 - 13  2013

  • Structure and activity of Ni/La<inf>0.7</inf>Sr<inf>0.3</inf>AlO <inf>3-δ</inf> catalyst for hydrogen production by steam reforming of toluene

    Daiki Mukai, Satoshi Tochiya, Yuki Murai, Masaya Imori, Yukihiro Sugiura, Yasushi Sekine

    Applied Catalysis A: General   464-465   78 - 86  2013  [Refereed]

     View Summary

    We investigated catalytic steam reforming of aromatic hydrocarbon using toluene as a model compound. Ni/La0.7Sr0.3AlO 3-δ catalyst showed high catalytic activity and low coke formation. Although the lattice oxygen in a perovskite-type support plays an important role for oxidizing CHx and coke precursor, the role of interaction between Ni and the support has not been clarified. In this study, Ni/La0.7Sr0.3AlO3-δ catalyst calcined at various temperatures (1073, 1173, 1273 and 1373 K) was prepared and used to elucidate the effect of Ni particle size on the lattice oxygen mobility. The Ni particle size increased concomitantly with increased calcination temperature, and the C1 yield decreased from 72.9 to 15.5%. Enhancement of lattice oxygen mobility by the decrease of Ni particle size was observed by transient response tests using H218O over Ni/La0.7Sr 0.3AlO3-δ calcined at various temperatures. The interface between Ni and perovskite support played an important role for oxidizing coke precursor by lattice oxygen. © 2013 Elsevier B.V. All rights reserved.

    DOI

  • Stable and selective perovskite catalyst for dehydrogenation of propane working with redox mechanism

    Ryo Watanabe, Yoshiaki Hondo, Kei Mukawa, Choji Fukuhara, Eiichi Kikuchi, Yasushi Sekine

    Journal of Molecular Catalysis A: Chemical   377   74 - 84  2013  [Refereed]

     View Summary

    Dehydrogenation of propane with steam was investigated using novel LaCoxMn1-xO3 (0≤x≤1) perovskite-type oxide (ABO3) catalysts. Optimization of the Co substitution ratio (x = 0.2) enabled high propylene yield and selectivity. The perovskite structure of LaCO0.2Mn0.8O3 remained stable during dehydrogenation, as confirmed by XRD measurements. Dehydrogenation of propane over LaCo0.2Mn0.8O3 perovskite catalyst proceeded via reduction-oxidation (redox) of the perovskite oxide; oxidative dehydrogenation of propane consumed lattice oxygen in the perovskite and the consumed lattice oxygen was regenerated by H2O. Surface analyses conducted using XPS and XANES showed that a part of Mn4+ and Co 3+ in LaCo0.2Mn0.8O3 was reduced to Mn3+ and Co2+ during the reaction. The LaCo 0.2Mn0.8O3 catalyst showed higher selectivity at the same propane conversion compared with the selectivity to propylene over an industrial CrOx/γ-Al2O3 catalyst. © 2013 Elsevier B.V. All rights reserved.

    DOI

  • Oxidative coupling of methane using carbon dioxide in an electric field over La-ZrO<inf>2</inf> catalyst at low external temperature

    Kazumasa Oshima, Keisuke Tanaka, Tomohiro Yabe, Eiichi Kikuchi, Yasushi Sekine

    Fuel   107   879 - 881  2013  [Refereed]

     View Summary

    Oxidative coupling of methane using carbon dioxide (CO2-OCM) as an oxidant was conducted over several La- and Zr-based catalysts in an electric field at low external temperature of 423 K. Higher catalytic activity was obtained than in a conventional catalytic reaction over 10 mol% lanthanum-doped zirconia (La-ZrO2) in the electric field. Although the catalytic activity for the CO2-OCM was low over the La-ZrO2 at 1173 K without the application of the electric field, the electric field promoted catalytic activity even at 423 K external temperature. We optimized the amount of doping-La in the La-ZrO2 system, and characterized the effect of doping-La with XRD measurement. From these examinations, 5 mol% La-ZrO 2 catalyst showed the highest activity. High catalytic activity was provided by the synergistic effect of the La-cation, tetragonal-ZrO2, and the electric field. © 2013 Elsevier Ltd. All rights reserved.

    DOI

  • Methane conversion assisted by plasma or electric field

    Kazumasa Oshima, Tatsuya Shinagawa, Yasushi Sekine

    Journal of the Japan Petroleum Institute   56 ( 1 ) 11 - 21  2013  [Refereed]

     View Summary

    Direct conversion of methane to other valuable products such as ethylene, methanol, benzene, carbon, hydrogen, and syngas has been widely investigated. Such conversion requires high temperatures because of the strong C-H bond in CH4, and such high-temperature reactions present various problems: sequential reaction to decrease the selectivity to target products, need for multiple heat exchangers to use or recover high-temperature waste heat, materials that are stable at high temperatures, etc. To solve these problems, several trials have been undertaken to lower reaction temperatures using plasma, Non-Faradaic Electrochemical Modification of Catalytic Activity (NEMCA), and electric fields. This review describes recent trends in methane conversion, and describes our methods to lower the reaction temperature.

    DOI

  • Plasma-assisted oxidation of carbon particle by lattice oxygen on/in oxide catalyst

    Yasushi Sekine, Hiroshi Koyama, Masahiko Matsukata, Eiichi Kikuchi

    Fuel   103   2 - 6  2013.01  [Refereed]

     View Summary

    Oxidation of carbon particles by lattice oxygen on/in catalysts was investigated with and without electrical discharge at 673 K in a fluidized bed reactor. Application of dielectric barrier discharge promoted the evolution of lattice oxygen in the oxide catalyst, and oxidation of carbon by the evolved lattice oxygen was accelerated by application of the discharge. The total amount of consumed lattice oxygen in/on the catalyst was not changed by the application of the discharge due to the low diffusion rate of bulk oxygen at low temperature. Metal-loaded catalysts such as Ni/CeO2 evolved larger amounts of lattice oxygen because of interaction between the supported Ni particle and ceria support. © 2012 Elsevier Ltd. All rights reserved.

    DOI

  • Low temperature ignition of methane partial oxidation over Ni/LaAlO <inf>3</inf> catalyst

    Daiki Mukai, Toshinari Eda, Keisuke Tanaka, Eiichi Kikuchi, Yasushi Sekine

    Journal of the Japan Petroleum Institute   56 ( 3 ) 156 - 164  2013  [Refereed]

     View Summary

    Low temperature partial oxidation of methane to produce syngas was investigated over Ni catalysts supported on various perovskite oxides. Pre-reduced Ni catalyst supported on LaAlO3 perovskite showed high catalytic activity at 673 K, the lowest temperature reported to date. Ni particles on LaAlO3 perovskite showed weaker interaction between metal and support, and were reduced at lower temperature than on other Ni catalysts. Partial oxidation proceeded via methane combustion and steam reforming, and the reduced Ni particles were active sites for both of these reactions. Additional impregnation of Pd enabled catalysis of the reaction without pre-reduction. The functions of Ni particles, LaAlO3 perovskite, and supported Pd were investigated by various methods, and found that Pd promoted the oxidation of methane, and catalytic partial oxidation proceeded over reduced Ni.

    DOI

  • In situ IR study for elucidating reaction mechanism of toluene steam reforming over Ni/La<inf>0.7</inf>Sr<inf>0.3</inf>AlO<inf>3-δ</inf> catalyst

    Daiki Mukai, Yuki Murai, Takuma Higo, Satoshi Tochiya, Takashi Hashimoto, Yukihiro Sugiura, Yasushi Sekine

    Applied Catalysis A: General   466   190 - 197  2013  [Refereed]

     View Summary

    Steam reforming of toluene as a model compound of biomass tar was conducted on supported Ni catalysts. The Ni catalyst supported on perovskite oxide (La0.7Sr0.3AlO3-δ: LSAO) showed the highest toluene conversion (58%) and lowest coke formation (57 mg g-cat -1) at 873 K thanks to the smaller Ni particle size and larger perimeter between Ni and perovskite support, confirmed by XRD, BET, STEM and XAFS. In this paper, adsorption of toluene on Ni/LSAO catalyst was investigated using FT-IR method to estimate the reaction mechanism. IR spectra during temperature programmed desorption revealed that strong adsorption of toluene was observed only on LSAO and Ni/LSAO. The decomposition of adsorbate to CO or CO2 was promoted by supported Ni metal. Lattice oxygen of perovskite support contributed to the oxidation of the intermediate at the interface of Ni and perovskite. In addition, the oxidation of intermediate was promoted by introducing steam. Investigating adsorptions of various probe molecules (benzene, n-heptane, ethylene and benzaldeyde) revealed that decomposition of aromatic ring proceeded on Ni/LSAO. © 2013 Elsevier B.V. All rights reserved.

    DOI

  • Dehydrogenation of ethylbenzene over La<inf>0.8</inf>Ba <inf>0.2</inf>Fe<inf>0.4</inf>Mn<inf>0.6</inf>O<inf>3-δ</inf> perovskite oxide catalyst working by redox mechanism using steam and lattice oxygen

    Ryo Watanabe, Kei Mukawa, Jungo Kojima, Eiichi Kikuchi, Yasushi Sekine

    Applied Catalysis A: General   462-463   168 - 177  2013  [Refereed]

     View Summary

    Details of the reaction mechanism of ethylbenzene (EBDH) dehydrogenation were investigated using kinetic analyses of highly active and stable La 0.8Ba0.2Fe0.4Mn0.6O 3-δ (LBFMO) perovskite oxide catalyst with a quadrupole mass spectrometer by measuring the instantaneous behavior. Under EBDH with a steam condition, the stoichiometric factor of oxygen in LBFMO catalyst in the steady-state reaction was found to be 2.927, which is lower than 3. The catalyst worked in the reduced state in which a few layers of lattice oxygen were consumed, supported by X-ray photoelectron spectroscopic analyses. Additionally, the reactive lattice oxygen and vacancy were involved with the reduction-oxidation (redox) mechanism of EBDH with steam. The respective amounts were 17.0 mmol mol-cat-1 for available lattice oxygen and 68.5 mmol mol-cat-1 for vacancy over LBFMO under the steady state condition. LBFMO catalyst showed high and stable EBDH activity by virtue of the redox mechanism using this lattice oxygen and vacancy. © 2013 Elsevier B.V. All rights reserved.

    DOI

  • Alkylation of isobutane by 1-butene over H-beta zeolite in CSTR (Part 3) effect of property of h-beta zeolite

    Yuki Kato, Shinya Fujioka, Keita Nakabayashi, Yo Suke Ichikawa, Eiichi Kikuchi, Yasushi Sekine

    Journal of the Japan Petroleum Institute   56 ( 5 ) 349 - 355  2013  [Refereed]

     View Summary

    H-beta (*BEA) zeolite catalyst has high activity/stability for the alkylation of isobutane with 1-butene in a CSTR, based on the catalytic nature of H-*BEA. Various preparation methods for H- *BEA were investigated to optimize the catalytic activity for alkylation, including Si/Al ratio, H+/Na+ ion exchange rate, and grain size of zeolite. The relationship between Brønsted acid amount and butene consumption over the catalyst lifetime showed a positive correlation. H-*BEA zeolite with larger grain size and prepared with longer crystallization time achieved higher alkylate yield based on the higher hydride transfer activity.

    DOI

  • Effect of Co addition to Ni/a-Al2O3 for partial oxidation of methane at low temperature

    Eda Toshinari, Mukai Daiki, Tanaka Keisuke, Kikuchi Eiichi, Sekine Yasushi

    Proceeding of Annual/Fall Meetings of the Japan Petroleum Institute   2012   69 - 69  2012

    DOI CiNii

  • Oxidative reaction of methane over Pt/LaSrAlOx catalyst and its specific structure

    Mukai Daiki, Tanaka Keisuke, Kikuchi Eiichi, Sekine Yasushi

    Proceeding of Annual/Fall Meetings of the Japan Petroleum Institute   2012   70 - 70  2012

    DOI CiNii

  • 特殊反応場としての放電・電場利用による天然ガスの低温転換

    関根 泰, 田中啓介, 大島一真, 品川竜也

    日本エネルギー学会誌   91 ( 9 ) 875 - 879  2012

  • メタンの酸化カップリングによるエチレンの合成

    関根 泰, 田中啓介

    ファインケミカル   41 ( 12 ) 28 - 33  2012

  • Oxidative coupling of methane over Ba-incorporated LaInO <inf>3</inf> perovskite catalyst

    Keisuke Tanaka, Yasushi Sekine, Jyunki Inoue, Hiroto Araki, Masahiko Matsukata, Eiichi Kikuchi

    Journal of the Japan Petroleum Institute   55 ( 1 ) 71 - 72  2012  [Refereed]

     View Summary

    We found that LaInO 3 perovskite catalyst showed high activity for oxidative coupling of methane (OCM). Partial substitution of La 3+ site in the LaInO 3 catalyst with Ba 2+ increased its catalytic activity and selectivity to C2 hydrocarbons drastically. The partial substitution of La 3+ site in LaInO 3 with Ba 2+ increased oxygen vacancies in the stable cubic phase, and then contributed to the production of active oxygen species on its surface for selective C2 formation.

    DOI

  • Catalytic oxidative coupling of methane with a dark current in an electric field at low external temperature

    K. Oshima, K. Tanaka, T. Yabe, Y. Tanaka, Y. Sekine

    International Journal of Plasma Environmental Science and Technology   6 ( 3 ) 266 - 271  2012  [Refereed]

     View Summary

    Oxidative coupling of methane (OCM) assisted by a dark current in an electric field was investigated at low external temperature (423 K). The Sr-La2O3 catalyst showed higher yield of C2 (C2H4, C2H6) in the electric field than in the conventional catalytic reaction. Catalytic properties in the electric field and electrical properties of the catalyst were investigated. Results show that the electrical conductivity of dark current of the catalyst is an important factor for applying the electric field. A higher CH4/O2 ratio enabled high selectivity to C2 hydrocarbons. The maximum selectivity to C2 hydrocarbons was 59%.

  • Catalytic oxidative coupling of methane assisted by electric power over a semiconductor catalyst

    Keisuke Tanaka, Yasushi Sekine, Kazumasa Oshima, Yoshitaka Tanaka, Masahiko Matsukata, Eiichi Kikuchi

    Chemistry Letters   41 ( 4 ) 351 - 353  2012  [Refereed]

     View Summary

    Oxidative coupling of methane (OCM) on La 2O 3 semiconductor catalysts at 423 K external temperature was investigated. DC power supplied from two electrodes in a catalyst bed enabled stable and selective production of C 2H 6 and C 2H 4 over Sr-La 2O 3 (Sr/La = 1/200 and 1/20), but plasma reactions proceeded over other catalysts. The electrical conductivity of the semiconductor catalyst was important for controlling this reaction. A high yield of C2 (49% selectivity, 51.3% O 2 conversion) was obtained using 2.7 W of electricity at a lower external temperature (423 K). © 2012 The Chemical Society of Japan.

    DOI

  • Alkylation of isobutane by 1-butene over H-beta zeolite in CSTR (Part 2) deactivation mechanism of zeolite catalyst and optimization of CSTR conditions

    Yasushi Sekine, Yu Ichi Tajima, Yo Suke Ichikawa, Masahiko Matsukata, Eiichi Kikuchi

    Journal of the Japan Petroleum Institute   55 ( 5 ) 308 - 318  2012  [Refereed]

     View Summary

    DGC-H-beta zeolite catalyst has higher activity and selectivity for the alkylation of isobutane with 1-butene in a CSTR. The cause of the deactivation of the catalyst and the optimum reaction conditions were investigated. Deactivation of the catalyst was caused not by adsorbed carbon species but by hydrocarbons formed by multiple alkylation or oligomerization of olefin. Optimized conditions to avoid these reactions achieved stable selective alkylation.

    DOI

  • Alkylation of isobutane by 1-butene over H-beta zeolite in CSTR (Part 1) effects of zeolite-structures and synthesis methods on alkylation performance

    Yasushi Sekine, Yo Suke Ichikawa, Yu Ichi Tajima, Keita Nakabayashi, Masahiko Matsukata, Eiichi Kikuchi

    Journal of the Japan Petroleum Institute   55 ( 5 ) 299 - 307  2012  [Refereed]

     View Summary

    The effects of zeolite structures on alkylation of isobutane with 1-butene were investigated in a batch reactor and in a continuously stirred tank reactor (CSTR) using the proton-form zeolites, H-ZSM-5, H-L, H-Y, and H- *BEA (beta). H-ZSM-5 and H-L zeolite catalysts were deactivated rapidly, whereas H-Y and H-*BEA zeolites retained catalytic activity for a long time in the CSTR, implying that zeolites with three-dimensional large pore systems are useful for preventing deactivation of the catalyst during alkylation of isobutane with 1-butene. H- *BEA synthesized using a dried-gel method (DGC-H-*BEA) showed the most stable activity among the various H-*BEA zeolites. The effects of the synthesis methods and zeolite characteristics were investigated using H-*BEA zeolite. Characterization using NH 3-TPD and pyridine-sorption monitored by FT-IR showed that high acid density and high Brønsted acid ratio promoted alkylation of isobutane with 1-butene over H-*BEA zeolite.

    DOI

  • Low temperature steam reforming of methane over metal catalyst supported on Ce<inf>x</inf>Zr<inf>1-x</inf>O<inf>2</inf> in an electric field

    Yasushi Sekine, Masayuki Haraguchi, Masahiko Matsukata, Eiichi Kikuchi

    Catalysis Today   171 ( 1 ) 116 - 125  2011.08  [Refereed]

     View Summary

    Catalytic steam reforming of methane in an electric field (named "electreforming") was conducted over metal catalysts supported on CeO2 or CexZr1-xO2 at low temperatures such as 423 K where conventional catalytic reactions hardly proceeded. The conversion of methane was greatly increased by weak and effective application of an electric field to the catalyst bed. Use of Ce xZr1-xO2 as a catalyst support promoted electreforming, the lattice oxygen of CexZr1-xO 2 playing an important role. Energy efficiency of electreforming, reaction mechanism, and the role of lattice oxygen were investigated and are discussed in this paper. © 2011 Elsevier B.V. All rights reserved.

    DOI

  • Coke-free dry reforming of model diesel fuel by a pulsed spark plasma at low temperatures using an exhaust gas recirculation (EGR) system

    Yasushi Sekine, Naotsugu Furukawa, Masahiko Matsukata, Eiichi Kikuchi

    Journal of Physics D: Applied Physics   44 ( 27 ) 274004 - 274004  2011.07  [Refereed]

     View Summary

    Dry reforming of diesel fuel, an endothermic reaction, is an attractive process for on-board hydrogen/syngas production to increase energy efficiency. For operating this dry reforming process in a vehicle, we can use the exhaust gas from an exhaust gas recirculation (EGR) system as a source of carbon dioxide. Catalytic dry reforming of heavy hydrocarbon is a very difficult reaction due to the high accumulation of carbon on the catalyst. Therefore, we attempted to use a non-equilibrium pulsed plasma for the dry reforming of model diesel fuel without a catalyst. We investigated dry reforming of model diesel fuel (n-dodecane) with a low-energy pulsed spark plasma, which is a kind of non-equilibrium plasma at a low temperature of 523 K. Through the reaction, we were able to obtain syngas (hydrogen and carbon monoxide) and a small amount of C2 hydrocarbon without coke formation at a ratio of CO 2/Cfuel = 1.5 or higher. The reaction can be conducted at very low temperatures such as 523 K. Therefore, it is anticipated as a novel and effective process for on-board syngas production from diesel fuel using an EGR system. © 2011 IOP Publishing Ltd.

    DOI

  • Dehydrogenation of ethylbenzene over highly active and stable perovskite oxide catalyst - Effect of lattice oxygen on/in perovskite oxide and role of A/B site in perovskite oxide

    Ryo Watanabe, Yasushi Sekine, Jungo Kojima, Masahiko Matsukata, Eiichi Kikuchi

    Applied Catalysis A: General   398 ( 1-2 ) 66 - 72  2011.05  [Refereed]

     View Summary

    Previously we reported that La0.8Ba0.2Fe 0.4Mn0.6O3-δ (LBFMO) perovskite oxide catalyst showed extremely high activity for dehydrogenation of ethylbenzene to produce styrene. The reaction mechanism of dehydrogenation of ethylbenzene over LBFMO catalyst and the role of A/B site cation in the perovskite were investigated using transient response experiments and thermogravimetric analyses in a H2O/H2 atmosphere. Results showed that the dehydrogenation of ethylbenzene over LBFMO perovskite catalyst proceeded via reduction-oxidation (redox) of the perovskite oxide in this temperature range (800-900 K). Thereby, oxidative dehydrogenation of ethylbenzene consumed lattice oxygen in the perovskite; the consumed lattice oxygen was regenerated by H 2O. We measured the lattice oxygen release rate and regenerating rate over LBFMO perovskite catalyst. The regeneration rate of lattice oxygen was almost equal to the formation rate of styrene in the steady state of the dehydrogenation reaction. Substituting the B site of perovskite with Fe has a stabilizing effect for the lattice oxygen in the perovskite, and enhanced the regeneration rate of lattice vacancy drastically using steam. We concluded that the better stability of LBFMO than that of other catalysts was derived from enhanced lattice oxygen regeneration in the perovskite. © 2011 Elsevier B.V.

    DOI

  • Alkylation of isobutane with 1-butene over acid type zeolite

    Sekine Yasushi, Fujioka Shinjya, Kato Youki, Matsukata Masahiko, Kikuchi Eiichi

    Proceeding of Annual/Fall Meetings of the Japan Petroleum Institute   2011   42 - 42  2011

    DOI CiNii

  • Low temperature catalytic reaction assisted by electric field

    Sekine Yasushi

    Proceeding of Annual/Fall Meetings of the Japan Petroleum Institute   2011   76 - 76  2011

    DOI CiNii

  • Development of the catalyst which has high activity for partial oxidation of methane at low temperature without noble metals

    Tanaka Keisuke, Sekine Yasushi, Mukai Daiki, Matsukata Masahiko, Kikuchi Eiichi

    Proceeding of Annual/Fall Meetings of the Japan Petroleum Institute   2011   71 - 71  2011

    DOI CiNii

  • Effect of trace amount addition of iron onto cobalt catalyst for steam reforming of ethanol

    Sekine Yasushi, Ohyama Koji, Matsukata Masahiko, Kikuchi Eiichi

    Proceeding of Annual/Fall Meetings of the Japan Petroleum Institute   2011   75 - 75  2011

    DOI CiNii

  • Optimization of the Ni/perovskite catalyst in the steam reforming of the aromatic hydrocarbon

    Sekine Yasushi, Murai Yuki, Tochiya Satoshi, Mukai Daiki, Matsukata Masahiko, Kikuchi Eiichi

    Proceeding of Annual/Fall Meetings of the Japan Petroleum Institute   2011   74 - 74  2011

    DOI CiNii

  • Oxidative coupling of methane over La-perovskite-oxide catalyst

    Tanaka Keisuke, Sekine Yasushi, Inoue Jun-ki, Araki Hiroto, Matsukata Masahiko, Kikuchi Eiichi

    Proceeding of Annual/Fall Meetings of the Japan Petroleum Institute   2011   159 - 159  2011

    DOI CiNii

  • Development of novel catalysts utilizing redox catalyses of perovskite-type oxide for propane dehydrogenation

    Watanabe Ryo, Hondo Yoshiaki, Sekine Yasushi, Matsukata Masahiko, Kikuchi Eiichi

    Proceeding of Annual/Fall Meetings of the Japan Petroleum Institute   2011   150 - 150  2011

    DOI CiNii

  • Dehydrogenation of ethylbenzene on rare-earth free perovskite-type oxide catalysts

    Sekine Yasushi, Watanabe Ryo, Ikushima Maiko, Nakano Kei, Matsukata Masahiko, Kikuchi Eiichi

    Proceeding of Annual/Fall Meetings of the Japan Petroleum Institute   2011   148 - 148  2011

    DOI CiNii

  • Low temperature catalytic oxidative coupling of methane assisted by an electric field

    Tanaka Keisuke, Sekine Yasushi, Ohshima Kazumasa, Tanaka Yoshitaka, Matsukata Masahiko, Kikuchi Eiichi

    Proceeding of Annual/Fall Meetings of the Japan Petroleum Institute   2011   160 - 160  2011

    DOI CiNii

  • Review on Prospects for Energy Saving in Distillation Process with Microporous Membranes

    Masahiko Matsukata, Ken ichi Sawamura, Yasushi Sekine, Eiichi Kikuchi

    Membrane Science and Technology   14   175 - 193  2011  [Refereed]

     View Summary

    This review describes prospects for energy saving in the chemical and petroleum industries and recommends that increasing efforts be exerted on the development of membrane-based separation systems. A preliminary estimate suggests that the simple addition of a membrane separation unit to an existing separation system or distillation unit can drastically reduce energy consumption by more than 70%. This review also describes state-of-the-art of zeolite-based separation membranes, which is the one of the most promising technologies among emerging separation methods. © 2011 Elsevier B.V.

    DOI

  • 大気圧非平衡プラズマと触媒を用いたエネルギー転換プロセス・水素製造

    関根 泰

    化学工学   75(6)   373 - 375  2011

  • Effect of loading potassium and palladium over iron-based catalyst for low temperature water-gas shift reaction

    Yasushi Sekine, Takahiro Chihara, Ryo Watanabe, Yuji Sakamoto, Masahiko Matsukata, Eiichi Kikuchi

    Catalysis Letters   140 ( 3-4 ) 184 - 188  2010.12  [Refereed]

     View Summary

    We investigated the effect of loading potassium over iron-based catalysts for water-gas shift (WGS) reaction at 573 K. The iron-based water-gas shift catalyst has been known as a redox-mechanism catalyst. Therefore, to promote the redox reaction over iron oxide, we impregnated a small amount of Pd on various iron oxides. Results revealed that coexisting potassium and palladium accelerated the WGS reaction over iron-oxide catalyst. We examined the optimum amount of potassium over Pd/iron catalyst, and we found that the optimum molar ratio was about 2 (K/Pd molar ratio). From the viewpoint of reducibility of the catalyst, the addition of small amount of Pd onto iron oxide promotes reduction from Fe2O3 to Fe3O4. However, impregnation of potassium on iron oxide makes the catalyst structure robust. The promotion effect of Pd and potassium was not observed on SiO2 support. We therefore concluded that the synergetic effect among Pd, K, and iron oxide, was important for the WGS reaction. © 2010 Springer Science+Business Media, LLC.

    DOI

  • Promoting effect of small amount of Fe addition onto Co catalyst supported on α-Al<inf>2</inf>O<inf>3</inf> for steam reforming of ethanol

    A. Kazama, Y. Sekine, K. Oyama, M. Matsukata, E. Kikuchi

    Applied Catalysis A: General   383 ( 1-2 ) 96 - 101  2010.07  [Refereed]

     View Summary

    We examined the promotion effect of loading small amounts of Fe onto various Co catalysts for steam reforming of ethanol. Among these catalysts, catalysts supported on SrTiO3 and α-Al2O3 showed remarkable effects of iron loading onto cobalt catalyst. The Fe-loaded Co/α-Al2O3 showed higher yield of hydrogen, low coke deposition on the catalysts, and high activity for steam reforming of acetaldehyde, which was an intermediate of the steam reforming of ethanol. Characterization of the catalyst revealed that Fe and Co metal coexisted on the catalyst support. Synergetic effects of these two metals were observed. © 2010 Elsevier B.V. All rights reserved.

    DOI

  • Pt and/or Pd supported/incorporated catalyst on perovskite-type oxide for water gas shift reaction

    R. Watanabe, Y. Sekine, H. Takamatsu, Y. Sakamoto, S. Aramaki, M. Matsukata, E. Kikuchi

    Topics in Catalysis   53 ( 7-10 ) 621 - 628  2010.06  [Refereed]

     View Summary

    Catalytic properties of Pd and/or Pt supported/incorporated on/in perovskite-type oxides for water gas shift (WGS) reaction have been investigated. We found that the dominant reaction mechanism over these catalysts was redox mechanism by CO and steam, and their redox properties were controllable by the bulk structure of perovskite. © 2010 Springer Science+Business Media, LLC.

    DOI

  • Low-temperature hydrogen production by highly efficient catalytic system assisted by an electric field

    Yasushi Sekine, Masayuki Haraguchi, Masahiko Tomioka, Masahiko Matsukata, Eiichi Kikuchi

    Journal of Physical Chemistry A   114 ( 11 ) 3824 - 3833  2010.03  [Refereed]

     View Summary

    We investigated four catalytic reactions assisted with an electric field to promote catalytic activity, and we could achieve an effective process for hydrogen production at low temperatures, such as 423 K. In the presence of the electric field, four reactions of steam reforming of ethanol, decomposition of ethanol, water gas shift, and steam reforming of methane proceeded at very low temperature, such as 423 K, where a conventional catalytic reaction hardly proceeded. Conversion of reactant was greatly increased by the electric field, and apparent activation energies for these four reactions were lowered by the application of the electric field. This process can produce hydrogen and syngas by using a considerably small energy demand and has quick response. © 2010 American Chemical Society.

    DOI PubMed

  • Steam reforming of toluene over supported nickel catalysts

    Sekine Yasushi, Hosomura Naomi, Sekiguchi Kei, Oku Yuki, Mizuno Shota, Izutu Yoshiyuki, Matsukata Masahiko, Kikuchi Eiichi

    Proceeding of Annual/Fall Meetings of the Japan Petroleum Institute   2010   39 - 39  2010

    DOI CiNii

  • Reaction mechanism of catalysts supported on perovskite type oxide for water gas shift reaction

    Sekine Yasushi, Sakamoto Yuki, Watanabe Ryo, Inoue Junki, Matsukata Masahiko, Kikuchi Eiichi

    Proceeding of Annual/Fall Meetings of the Japan Petroleum Institute   2010   53 - 53  2010

    DOI CiNii

  • Low temperature catalytic steam reforming of methane in an electric field

    Sekine Yasushi, Haraguchi Masayuki, Ohshima Kazuma, Matsukata Masahiko, Kikuchi Eiichi

    Proceeding of Annual/Fall Meetings of the Japan Petroleum Institute   2010   41 - 41  2010

    DOI CiNii

  • Steam refoming of toluene over Ni/perovskite catalyst

    Sekine Yasushi, Sekiguchi Kei, Mizuno Shota, Hosomura Naomi, Matsukata Masahiko, Kikuchi Eiichi

    Proceeding of Annual/Fall Meetings of the Japan Petroleum Institute   2010   144 - 144  2010

    DOI CiNii

  • 水素製造・吸蔵・貯蔵材料と安全化、サイエンス&テクノロジー、p.116-125、2010

    関根 泰

       2010

  • 究極のエネルギーと環境調和、日刊工業新聞社、p.165-175, 2010

    関根 泰

       2010

  • Simultaneous dry reforming and desulfurization of biomethane with non-equilibrium electric discharge at ambient temperature

    Yasushi Sekine, Junya Yamadera, Masahiko Matsukata, Eiichi Kikuchi

    Chemical Engineering Science   65 ( 1 ) 487 - 491  2010  [Refereed]

     View Summary

    We investigated two types of electrical discharges for converting biomethane into syngas at ambient temperature and atmospheric pressure. Low energy pulsed discharge (LEP) has a good property for this reaction and it could convert biomethane into syngas and also H2S was converted into solid sulfur simultaneously. This is due to the high electron energy of LEP, and the electron has enough energy to dissociate C-C bond and C-S bond. On the other hand, dielectric barrier discharge could convert H2S into solid sulfur, but methane and CO2 in the biomethane were not reacted at lower input power. Our investigation showed that proper choice of electric discharge could bring selective reaction for dry reforming of biomethane and desulfurization, and this was due to the correlation between the bond dissociation energy of each molecule and electron energy level of each discharge. © 2009 Elsevier Ltd. All rights reserved.

    DOI

  • Steam reforming of ethanol over cobalt catalyst modified with small amount of iron

    Yasushi Sekine, Atsushi Kazama, Yoshiyuki Izutsu, Masahiko Matsukata, Eiichi Kikuchi

    Catalysis Letters   132 ( 3-4 ) 329 - 334  2009.10  [Refereed]

     View Summary

    Steam reforming of ethanol was examined over Co/SrTiO3 with addition of another metal-Pt, Pd, Rh, Cr, Cu, or Fe-for promotion of the catalytic activity. Ethanol conversion and H2 yield were improved greatly by adding Fe or Rh at 823 K. Although Rh addition promoted CH 4 formation, Fe addition enhanced steam reforming of ethanol selectively. A suitable amount of Fe loading was in the window of 0.33-1.3 mol%. A comparative study of the reaction over a catalyst supported on SiO 2 was conducted, but no additional effect of Fe was observed on the Co/SiO2 catalyst. High activity of Fe/Co/SrTiO3 catalyst came from interaction among Fe, Co, and SrTiO3. © 2009 Springer Science+Business Media, LLC.

    DOI

  • Catalytic degradation of ethanol in an electric field

    Y. Sekine, M. Tomioka, M. Matsukata, E. Kikuchi

    Catalysis Today   146 ( 1-2 ) 183 - 187  2009.08  [Refereed]

     View Summary

    We investigated novel catalytic reaction systems which were activated by an electric field. This is the first report for the synergetic effect of catalyst and electric field. These catalytic systems showed very high activity compared to conventional catalytic reaction systems. Although Pt supported on CeO2 catalyst without an electric field showed no activity at 473 K, the addition of an electric field to the catalyst promoted the degradation of ethanol. Pt/CeO2 catalyst was activated by the electric field and synergetic effect of Pt catalyst and electric field was observed. Thermal analyses showed that about 5-10% of input electrical power was wasted as a heat and about 90-95% was consumed for the endothermic reaction. Catalytic reactions in an electric field proceed under mild conditions and show a quick response. © 2009 Elsevier B.V. All rights reserved.

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  • Novel perovskite-type oxide catalysts for dehydrogenation of ethylbenzene to styrene

    Ryo Watanabe, Yasushi Sekine, Masahiko Matsukata, Eiichi Kikuchi

    Catalysis Letters   131 ( 1-2 ) 54 - 58  2009.08  [Refereed]

     View Summary

    We investigated novel LaMnOx perovskiteoxide (ABO3) catalysts for effective catalytic dehydrogenation of ethylbenzene to produce styrene monomer. Comparison with industrial Fe-K catalyst, our La0.8Ba 0.2 Mn0.6Fe0.4O3-δ catalyst showed higher activity. Results show that the A-site in perovskite-type oxides affected catalytic dehydrogenation activities and that the B-site affected stability of the activities. © Springer Science+Business Media, LLC 2009.

    DOI

  • Reverse-selective microporous membrane for gas separation

    Ken Ichi Sawamura, Teruaki Izumi, Kiyotoshi Kawasaki, Shintaro Daikohara, Tetsu Ohsuna, Mitsuko Takada, Yasushi Sekine, Eiichi Kikuchi, Masahiko Matsukata

    Chemistry - An Asian Journal   4 ( 7 ) 1070 - 1077  2009.07  [Refereed]

     View Summary

    Reverse-selective membranes,through which bigger molecules selectively permeate, are attractive for developing chemical processes utilizing hydrogen because they can maintain the high partial pressure of hydrogen required for their further downstream utilization. Although several of these chemical processes are operated above 473 K, membranes with outstanding reverse-selective separation performance at these temperatures are still to be reported. Herein, we propose a new adsorption-based reverse-selective membrane that utilizes a Na cation occluded in a zeolitic framework. The membrane developed in this work, a compact Na+-exchanged ZSM-5 (NaZSM-5) type zeolite membrane, enables us to selectively permeate and separate bigger polar molecules, such as methanol and water, from a stream containing hydrogen, above 473 K. On the other hand, a Na+-free, H+-exchanged ZSM-5 (HZSM-5) type zeolite membrane did not show separation properties at these temperatures. The microporous zeolite membrane developed in this study can be applied to a variety of chemical reaction systems to minimize energy consumption. ©2009 Wiley-VCH Verlag GmbH&Co. KGaA, Weinheim.

    DOI

  • Oxidative coupling of methane on fe-doped La<inf>2</inf>o<inf>3</inf> catalyst

    Yasushi Sekine, Keisuke Tanaka, Masahiko Matsukata, Eiichi Kikuchi

    Energy and Fuels   23 ( 2 ) 613 - 616  2009.02  [Refereed]

     View Summary

    Various La2O3-based catalysts are well-known to be useful for the oxidative coupling of methane (OCM reaction). We examined the catalytic activities of various La2O3-based OCM catalysts for the OCM reaction in the kinetic region (i.e., lower O2 conversion). Our investigation revealed that the Fe-doped La2O 3 catalyst is a good candidate for the OCM reaction. The La/Fe ratio of the Fe-doped La2O3 catalyst is an important factor for OCM activity. Especially, the O2-based C2 yield of the Fe-doped La2O3 catalyst was higher than that of La2O3 in the case of La/Fe > 5. The Fe-doped La2O3 catalyst modified with Na2O and Na4P2O7 showed high C2 selectivity (83%). Moreover, modification with Bi compounds also enhanced C2 selectivity of the Fe-doped La2O3 catalyst. This catalyst showed higher C2 yield than the Fe-doped La2O3 catalyst. © 2009 American Chemical Society.

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  • Synergistic effect of Pt or Pd and perovskite oxide for water gas shift reaction

    Yasushi Sekine, Haruka Takamatsu, Sho Aramaki, Kazuki Ichishima, Mitsuko Takada, Masahiko Matsukata, Eiichi Kikuchi

    Applied Catalysis A: General   352 ( 1-2 ) 214 - 222  2009.01  [Refereed]

     View Summary

    The water gas shift (WGS) reaction over Pt and Pd catalysts supported on various perovskite oxides has been investigated at 573 K without catalyst pretreatment. The Pt and Pd catalysts on LaCoO3 support showed high catalytic activity. Interaction between Pt or Pd and the support is considered to promote the WGS reaction: Pt/LaCoO3 had high initial activity but deactivated immediately; Pd/LaCoO3 was less active than Pt/LaCoO3, but had superior stability. Catalysts were characterized using XRD, STEM, XPS, and H2-temperature programmed reduction (TPR). Results of this study showed that reduction of the support decreased the CO conversion on Pt/LaCoO3. On the other hand, Pd/LaCoO3 showed stable activity for the WGS reaction. Therefore, Pd was added to Pt/LaCoO3 for stabilizing the catalyst activity, and 0.5 wt.% Pd/1 wt.% Pt/LaCoO3 catalyst showed higher activity and stability. © 2008 Elsevier B.V. All rights reserved.

    DOI

  • 7-2-3 Oxidation of solid carbon by hybrid process of oxide catalyst and non-equilibrium discharge

    SEKINE Yasushi, KOYAMA Hiroshi, MATSUKATA Masahiko, KIKUCHI Eiichi

    Proceedings of the Annual Conference of The Japan Institute of Energy   18   388 - 389  2009

     View Summary

    Low temperature catalytic oxidation of solid carbon was conducted in a fluidized bed reactor with a non-equilibrium discharge. Solid carbons like as soot, PM, and char cause many operational problems and have lower reactivity. We tried to oxidize such carbon particles to carbon dioxide by oxide catalysts with DBD discharge at lower temperature. Also to maintain high contact frequency between the catalyst and carbon particles, we applied a fluidized-bed reaction apparatus for this reaction. As a result, we found that carbon particles are oxidized at 673 K by the plasma-catalytic reaction with some oxide catalysts. Among various oxide catalysts, Pt/BaCeMnOx showed higher activity for the oxidation of carbon particles in the hybrid process of catalyst and plasma.

    DOI CiNii

  • 7-2-4 Direct decomposition of NO over plasma-assisted catalytic reaction

    SEKINE Yasushi, KOSUGE Kentaro, MATSUKATA Masahiko, KIKUCHI Eiichi

    Proceedings of the Annual Conference of The Japan Institute of Energy   18   390 - 391  2009

     View Summary

    Direct decomposition of nitric oxide (NO) was carried out with a plasma-assisted catalytic reaction system. As NO decomposition catalysts for the conversion of NO into N_2 and O_2, Ba/Ce-Mn-Ox and perovskite oxide were used as catalysts in this experiment. The combination of catalytic reaction and non-equilibrium electric discharge allows higher N_2 yield at low temperatures than catalytic reaction without plasma or non-equilibrium electric discharge without catalyst. And it was found that Ba/Ce-Mn-Ox is effective as a catalyst in this plasma-assisted catalytic reaction for direct decomposition of NO. Coexistence of oxygen or steam decreased N_2 yield drastically in this reaction. However, the synergistic effect of catalytic reaction and non-equilibrium electric discharge existed even though coexistence of oxygen or steam.

    DOI CiNii

  • 4-7-3 Low temperature methane steam reforming by catalytic reaction assisted with an electric field

    SEKINE Yasushi, HARAGUCHI Masayuki, TOMIOKA Masahiko, MATSUKATA Masahiko, KIKUCHI Eiichi

    Proceedings of the Annual Conference of The Japan Institute of Energy   18   284 - 285  2009

     View Summary

    To achieve lower reaction temperature and higher conversion than existing catalytic processes for hydrogen production, catalytic reaction of methane steam reforming in an electric field was conducted. Conversion of methane increased on catalytic reaction in the electric field by the interaction of electric field and catalyst. In the presence of the electric field, reaction proceeded in considerably low temperature where conventional catalytic reaction hardly proceeded. Then, to investigate response of catalytic reaction in the electric field, transient experiment was conducted. As a result, conversion of methane quickly increased with impressing of the electric field.

    DOI CiNii

  • Low temperature catalytic reaction with electric field

    Sekine Yasushi, Haraguchi Masayuki, Tomioka Masahiko, Matsukata Masahiko, Kikuchi Eiichi

    Proceeding of Annual/Fall Meetings of the Japan Petroleum Institute   2009   43 - 43  2009

     View Summary

    We found that catalytic steam reforming of methane was drastically promoted in an electric field. In the presence of the electric field, reaction proceeded in considerably low temperature region like as 423 K where conventional catalytic steam reforming of methane hardly proceeded. Conversion was greatly increased by impressing the electric field to the catalyst bed. This process can produce hydrogen and syngas by using considerably small energy demand and has a property of quick response.

    DOI CiNii

  • Development of novel redox-type catalyst for water gas shift reaction

    Sekine Yasushi, Watanabe Ryo, Chihara Takahiro, Sakamoto Yuki, Takamatu Haruka, Matsukata Masahiko, Kikuchi Eiichi

    Proceeding of Annual/Fall Meetings of the Japan Petroleum Institute   2009   54 - 54  2009

     View Summary

    Water-gas-shift (WGS) reaction is important for hydrogen production process and synthesis gas production process. In the industrial process, high-temperature-shift (HTS) reaction is carried out at 593-723 K using iron-chromium catalyst, and low-temperature-shift (LTS) reaction is carried out below 573 K using copper-zinc catalyst, respectively. There are some problems that the iron-chromium catalyst has low activity at low temperature, and the copper-zinc catalyst is deactivated by cyclic operation like as DSS. Recently we reported that the activity of Pd/Pt/LaCoO3 was higher than the activity of the copper-zinc catalyst and the catalyst did not require reductive pretreatment. The noble metal catalyst is comparatively stable, but the cost of the noble metal catalyst is higher than the iron-chromium catalyst and the copper-zinc catalyst. Therefore it is important to reduce the amount of noble metal.The purpose of this study is to develop the novel catalyst for the WGS reaction in order to decrease the reaction temperature, and we examined the iron oxide catalyst and perovskite type oxide catalyst, expecting to improve the activity and the heat stability with redox properties.

    DOI CiNii

  • Rapid crystallization of mesoporous silica with highly stable 2D-hexagonal structure

    Satoshi Inagaki, Yasuhiro Aratani, Satoshi Nakata, Yuichi Yashiro, Yasushi Sekine, Eiichi Kikuchi, Masahiko Matsukata

    Bulletin of the Chemical Society of Japan   82 ( 5 ) 606 - 612  2009  [Refereed]

     View Summary

    We investigated the synthetic parameters of MCM-41, prepared through the evaporation-to-dryness treatment of alkali-free surfactant-silicate mixture, and their thermal stability and water resistance. The product obtained by this method gave a well-ordered 2D-hexagonal structure after the removal of surfactant molecules by either solvent-extraction or calcination. It is noteworthy that the d 100 value of MCM-41 remained almost the same after calcination, indicating that the pore wallsof the as-made product were dense and rigid. This MCM-41 shows a high degree of thermal stability and water resistance due to the highly dense silicate framework in the mesopore walls. © 2009 The Chemical Society of Japan.

    DOI CiNii J-GLOBAL

  • Novel oxidation reaction at ambient temperature and atmospheric pressure with electric discharge and oxide surface

    Yasushi Sekine, Shinjiro Asai, Shigeru Kado, Masahiko Matsukata, Eiichi Kikuchi

    Chemical Engineering Science   63 ( 20 ) 5056 - 5065  2008.10  [Refereed]

     View Summary

    We investigated a novel oxidation reaction with surface-oxygen and lattice-oxygen induced using a non-equilibrium electric discharge at ambient temperature. We employed MgO, ZrO2, and TiO2 for this novel reaction. Methane was oxidized easily and converted into H2, CO, and CO2 by the surface-oxygen and lattice-oxygen of oxide with activation of discharge at ambient temperature without gas-phase oxygen. The oxide itself was stable after the reaction. Among these oxides, the tetragonal phase and amorphous phase of ZrO2 showed remarkably high activity for methane oxidation. Consequently, up to 8% of surface and lattice oxygen of the oxide was consumed by methane oxidation induced by electric discharge. The non-equilibrium electric discharge activated both the surface-oxygen and the lattice-oxygen of the oxides and methane molecules in the gas phase. After these reactions, the oxide surface vacant sites were recovered partially through steam post-treatment. Hydrogen formed simultaneously with steam decomposition. Other reactions were also studied by changing the reaction gas: methane into carbon monoxide, carbon monoxide with oxygen, and carbon monoxide with steam. Furthermore, the correlation of reactivity between the feed gas and surface oxygen was studied. Emission spectra under a CH4 atmosphere with electric discharge showed complex peaks caused by carbon monoxide formation at 280-500 nm at 0-4 min, suggesting that surface oxygen on oxides was probably consumed within 4 min from the start of the reaction. © 2007 Elsevier Ltd. All rights reserved.

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  • High performance of Fe-K oxide catalysts for dehydrogenation of ethylbenzene to styrene with an aid of ppm-order Pd

    Yasushi Sekine, Ryo Watanabe, Masahiko Matsukata, Eiichi Kikuchi

    Catalysis Letters   125 ( 3-4 ) 215 - 219  2008.10  [Refereed]

     View Summary

    Styrene is manufactured industrially through catalytic dehydrogenation of ethylbenzene on Fe-K oxide-based catalysts. It was invented by Süd-Chemie Group that the activity of the industrial ethylbenzene dehydrogenation catalysts (Styromax) based on the oxides of Fe and K is highly promoted by the addition of small amount (hundreds ppm-order) of precious metals such as Pd. The present work is intended to elucidate the role of Pd on the Fe-K catalyst empirically by use of a periodical pulse technique from a mechanistic point of view. The oxidative dehydrogenation was faster than the simple dehydrogenation, and it proceeded by consuming the surface lattice oxygen in the catalyst. The lattice oxygen was subsequently supplied from steam. Palladium added to the Fe-K oxide catalysts was found to enhance the rate of regeneration (supplying) of the lattice oxygen, although it hardly changed the rate of dehydrogenation of ethylbenzene or consumption of surface lattice O2- anions. This study demonstrated that steam works not only as a diluent but also as a reactant to form hydrogen and lattice oxygen. © 2008 Springer Science+Business Media, LLC.

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  • Controlled growth for synthesizing a compact mordenite membrane

    Masahiko Matsukata, Ken ichi Sawamura, Tsutomu Shirai, Mitsuko Takada, Yasushi Sekine, Eiichi Kikuchi

    Journal of Membrane Science   316 ( 1-2 ) 18 - 27  2008.05  [Refereed]

     View Summary

    Controlling the growth of zeolite crystals on a porous alumina support is essential for preparing a compact zeolite membarne. First, mordenite seed crystals applied on a nonporous α-alumina disk were grown and morphological change of mordenite crystals were observed in the course of growth. Then, mordenite membranes were synthesized on a porous α-alumina tube under the same conditions employed in the study using the alumina disks. We found that seed crystal growth was widely controllable by changing water content in reaction solution, which resulted in better control of the morphology of mordenite crystals for synthesizing a thin compact mordenite membrane. Separation properties for mordenite membranes were studied in water-hydrogen binary system at 473 K with 10 kPa of water partial pressure, where no capillary condensation was expected in non-zeolitic pores. Separation factor for a mordenite membrane with a few defects was poor; however, a defect-free mordenite membrane prepared under a suitable condition highly separated steam from hydrogen. © 2007 Elsevier B.V. All rights reserved.

    DOI

  • Production of hydrogen by steam reforming of ethanol over cobalt and nickel catalysts supported on perovskite-type oxides

    Kohei Urasaki, Kazuhisa Tokunaga, Yasushi Sekine, Masahiko Matsukata, Eiichi Kikuchi

    Catalysis Communications   9 ( 5 ) 600 - 604  2008.03  [Refereed]

     View Summary

    The steam reforming of ethanol was performed over Co and Ni catalysts supported on perovskite-type oxides (LaAlO3, SrTiO3 and BaTiO3). Co and Ni catalysts supported on LaAlO3 and SrTiO3 showed high catalytic activities and long-term stabilities and suppressed coke formation while Co/BaTiO3 showed lower catalytic activities and poorer coking resistance. The average particle size of Co on BaTiO3 was larger than that on SrTiO3. Lattice oxygen in perovskites may play positive roles in hindering coking and Co/SrTiO3 has more frequent participation of lattice oxygen in the oxidation of intermediates or precursor of coke in comparison with Co/BaTiO3. © 2007 Elsevier B.V. All rights reserved.

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  • Selective permeation and separation of steam from water-methanol-hydrogen gas mixtures through mordenite membrane

    Ken Ichi Sawamura, Tsutomu Shirai, Mitsuko Takada, Yasushi Sekine, Eiichi Kikuchi, Masahiko Matsukata

    Catalysis Today   132 ( 1-4 ) 182 - 187  2008.03  [Refereed]

     View Summary

    Separation properties of a mordenite membrane for water-methanol-hydrogen mixtures were studied in the temperature range from 423 to 523 K under pressurized conditions. The mordenite membrane was prepared on the outer surface of a porous alumina tubular support by a secondary-growth method. It was found that water was selectively permeated through the membrane. The separation factor of water/hydrogen and water/methanol were 49-156 and 73-101, respectively. Even when only hydrogen was fed at 0.5 MPa, its permeance was as low as 10-9 mol m-2 s-1 Pa-1 up to 493 K, possibly suggesting that water pre-adsorbed in the micropores of mordenite hindered the permeation of hydrogen. The hydrogen permeance dramatically increased to 6.5 × 10-7 mol m-2 s-1 Pa-1 at 503 K and reached to 1.4 × 10-6 mol m-2 s-1 Pa-1 at 523 K because of the formation of cracks in the membrane. However, the membrane was thermally stabilized in the presence of steam and/or methanol. © 2007 Elsevier B.V. All rights reserved.

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  • Release behavior of trace elements from coal during high-temperature processing

    Yasushi Sekine, Kunihisa Sakajiri, Eiichi Kikuchi, Masahiko Matsukata

    Powder Technology   180 ( 1-2 ) 210 - 215  2008.01  [Refereed]

     View Summary

    High-temperature coal utilization processes (combustion, gasification and pyrolysis) emit toxic trace elements into the atmosphere, where they affect the environment and human health. We carried out coal combustion and gasification experiments using several kinds of coals at various temperatures and atmospheric conditions to examine the release behavior of trace elements. Results showed that Group 1 and 2 metals such as Hg, Se, Sb, and Zn were partly released from coal during combustion, gasification and pyrolysis. Oxygen or steam in the operating atmosphere affected the behavior of Hg, Se, Sb, and Zn release from coal. © 2007 Elsevier B.V. All rights reserved.

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  • Separation behavior of steam from hydrogen and methanol through mordenite membrane

    Ken Ichi Sawamura, Tsutomu Shirai, Tetsu Ohsuna, Takayuki Hagino, Mitsuko Takada, Yasushi Sekine, Eiichi Kikuchi, Masahiko Matsukata

    Journal of Chemical Engineering of Japan   41 ( 9 ) 870 - 877  2008  [Refereed]

     View Summary

    A mordenite membrane was prepared on the outer surface of a porous α-alumina tubular support by a secondary-growth method. Permeation tests for water/methanol/hydrogen mixtures were performed at 423 and 473 K. A mordenite membrane free from non-zeolitic pores allowed us selective permeation of steam and blocked the permeation of hydrogen and methanol. In order to elucidate the mechanism of such selective permeation behavior, adsorption, permeation, and structural properties of the mordenite membrane were discussed. As a result, it was considered that selective permeation of steam against hydrogen was based on its preferential adsorption of steam, while boundaries between mordenite crystals in the membrane may play a key role for inhibiting the permeation of methanol. Copyright © 2008 The Society of Chemical Engineers, Japan.

    DOI

  • 水素製造のここ10年と未来

    菊地英一, 関根 泰

    触媒   50(1)   19 - 21  2008

  • ペロブスカイト型酸化物を用いた燃料電池用水性ガスシフト反応触媒の開発

    関根 泰, 菊地英一

    燃料電池   7 ( 4 ) 105 - 110  2008

  • Steam reforming of ethanol over Co/La<inf>1-x</inf>Sr<inf>x</inf>BO<inf>3</inf> (B=Al, Cr, Mn, Fe) catalysts

    Kohei Urasaki, Yoshie Fukuda, Yasushi Sekine, Masahiko Matsukata, Eiichi Kikuchi

    Journal of the Japan Petroleum Institute   51 ( 2 ) 83 - 87  2008  [Refereed]

     View Summary

    The steam reforming of ethanol for producing hydrogen was evaluated over 5 wt % Co catalysts supported on perovskite-type oxides, La1-xSrxBO3 (B=Al, Cr, Mn, Fe, x=0-0.2) at 823 K. Co/LaAlO3 showed higher catalytic activity and stability than Co catalysts supported on LaCrO3, LaFeO3 and LaMnO3. The molar La/Al ratio significantly influenced the stability of Co/LaAlO3 catalyst and a molar La/Al ratio of 1:1 was the most suitable, suggesting that the properties of the perovskite structure are important in the catalytic activity and stability. Partial substitution of Sr2+ for La3+ in LaAlO3 led to further remarkable improvement of catalytic activity and hydrogen yield. Enhanced mobility of lattice oxygen in La1-xSrxAlO3-δ allows more frequent participation in the oxidation of intermediates over metallic cobalt, leading to both high catalytic activity and stability of Co/La1-xSrxAlO3-δ in comparison with Co/LaAlO3.

    DOI

  • High-efficiency dry reforming of biomethane directly using pulsed electric discharge at ambient condition

    Yasushi Sekine, Junya Yamadera, Shigeru Kado, Masahiko Matsukata, Eiichi Kikuchi

    Energy and Fuels   22 ( 1 ) 693 - 694  2008.01  [Refereed]

     View Summary

    It is possible to directly convert biomethane into syngas at ambient temperatures and atmospheric pressure without gas cleaning, as showed by a recent experiment. The experiment made use of a flow-type reaction apparatus equipped with two oppositely charged electrodes and a high-voltage electric discharge within the electrode gas. Composed of a mixture of 59.7% methane and 40.2% carbon dioxide, the reaction gas has a flow rate of 20 cc/min. It was showed that the method is highly effective since total energy was very high and the H2S was converted straight to solid sulfur.

    DOI

  • Effective Utilization of Electrical Discharges for Hydrogen Production

    Y.Sekine, M.Matsukata, E.Kikuchi

    Int. J. Plasma Environmental Science and Technology   2   72 - 75  2008

  • Application of FAU-type zeolite membranes to vapor/gas separation under high pressure and high temperature up to 5 MPa and 180 °C

    Kiminori Sato, Kazunori Sugimoto, Yasushi Sekine, Mitsuko Takada, Masahiko Matsukata, Takashi Nakane

    Microporous and Mesoporous Materials   101 ( 1-2 SPEC. ISS. ) 312 - 318  2007.04  [Refereed]

     View Summary

    Tubular FAU-type zeolite membrane was synthesized on porous alumina substrate with 80 cm long by a seeded growth method. Pervaporation experiments using a mixture of water (10 wt%)/ethanol (90 wt%) at 75 °C demonstrated superior permeation properties of this type of membrane showing the total flux of 4-10 (kg m-2 h-1) with the separation factor of 110-300. A part of the synthesized membrane with 10 cm long was applied to gas separation at high pressures of 1-5 MPa and high temperatures of 130 and 180 °C. Ternary mixtures of water, methanol and hydrogen were used for evaluating the permselectivities of FAU-type membrane. It was found that hydrogen permeation was strongly depressed in the presence of water and methanol. Preferential adsorption of water and methanol in the micropores of FAU-type zeolite possibly played an important role for the appearance of permselectivity. © 2006 Elsevier Inc. All rights reserved.

    DOI

  • Catalytic degradation of ethanol at lower temperature with an aid of electric field

    Sekine Yasushi, Tomioka Masahiko, Matsukata Masahiko, Kikuchi Eiichi

    Proceeding of Annual/Fall Meetings of the Japan Petroleum Institute   2007   91 - 91  2007

     View Summary

    Novel catalytic reaction with high voltage electric field was conducted with a pyloritic reaction of ethanol as a model reaction. As a catalyst, Pt was supported on some of oxides, and high voltage electric field was applied on the catalyst. Pt supported ceria catalyst showed very high activity among these catalysts at lower temperature as 300 degree centigrade. Compare to conventional catalytic process, this novel system can be achieved at lower temperature with a high energy efficiency.

    DOI CiNii

  • Methane steam reforming over Ni catalyst supported on perovskite type oxide

    Sekine Yasushi, Doi Azusa, Nishizawa Tatsuhiko, Matsukata Masahiko, Kikuchi Eiichi

    Proceeding of Annual/Fall Meetings of the Japan Petroleum Institute   2007   2 - 2  2007

     View Summary

    On the steam reforming of methane, coke formation on the catalyst was severe problem which causes the deactivation of catalyst. So, suppressing the coke formation was expected for the fuel cell application. Up to now, we employed perovskite oxides as a support of catalyst which has mobile oxygen on/in the support, and conducted redox type steam reforming reaction with this catalyst. In this presentation, we tried to examine the effect of support on this reforming reaction.

    DOI CiNii

  • Alkylation of isobutane with 1-butene over zeolitic catalyst

    Sekine Yasushi, Ohmori Yuya, Tajima Yuhichi, Ichikawa Yohsuke, Matsukata Masahiko, Kikuchi Eiichi

    Proceeding of Annual/Fall Meetings of the Japan Petroleum Institute   2007   178 - 178  2007

    DOI CiNii

  • Release behavior of trace metals from coal during high temperature processing

    Y. Sekine, K. Sakajiri, R. Inoue, E. Kikuchi, M. Matsukata

    Studies in Surface Science and Catalysis   159   573 - 576  2006  [Refereed]

    DOI

  • Reactivity and structural change of coal char during steam gasification

    Yasushi Sekine, Kiyohiro Ishikawa, Eiichi Kikuchi, Masahiko Matsukata, Akemitsu Akimoto

    Fuel   85 ( 2 ) 122 - 126  2006.01  [Refereed]

     View Summary

    This study is intended to clarify the relationship among the reactivity of coal char with steam, structural change in residual carbon, and ash behavior. Steam gasification of various coal chars and demineralized chars was carried out in a fixed-bed reactor. After gasification, the reacted char was analyzed using laser raman spectroscope (LRS), and scanning electron microscope, energy dispersive X-ray spectroscope (SEM/EDX) mapping. Results of SEM images and EDX-mappings revealed that novel parallel analysis of cross correlation between EDX-mapping and LRS-mapping was found to be very effective for the comprehensive evaluation of ash behavior and carbonaceous structure. As the gasification reaction proceeds, the reactivity of the char was varied; existence of Si and Al seemed to suffocate the char reactivity. © 2005 Elsevier Ltd. All rights reserved.

    DOI

  • Hydrogen production from biomass-ethanol at ambient temperature with novel diaphragm reactor

    Y. Sekine, S. Asai, E. Kikuchi, M. Matsukata, F. Haga

    Studies in Surface Science and Catalysis   159   813 - 816  2006  [Refereed]

    DOI

  • The effect of hydrophilicity/hydrophobicity ratio of coal surface on the column flotation process

    Yasushi Sekine, Daisuke Sato, Daisuke Yamaguchi, Eiichi Kikuchi, Masahiko Matsukata

    Nihon Enerugi Gakkaishi/Journal of the Japan Institute of Energy   84 ( 11 ) 917 - 922  2005.11  [Refereed]

     View Summary

    Continuous column flotation is one of an economical coal cleaning processes. In this study, we examined the effect of hydrophilicity and hydrophobicitiy of coal surface on the continuous column flotation processes. We found that Wallarah coal was most suitable coal for the coal cleaning by the column flotation. From a static separation of film flotation, we found that the floatability of coal particle strongly depended on the hydrophilicity and hydrophobicity of coal surface. On the other hand, the trend of demineralization and the ratio of carbonaceous recovery could be predicted by the observation of methylene-blue adsorption test.

    DOI

  • Reaction and oxygen permeation studies in Sm<inf>0.4</inf>Ba <inf>0.6</inf>Fe<inf>0.8</inf>Co<inf>0.2</inf>O<inf>3 - δ</inf> membrane reactor for partial oxidation of methane to syngas

    Masayuki Ikeguchi, Tomohiro Mimura, Yasushi Sekine, Eiichi Kikuchi, Masahiko Matsukata

    Applied Catalysis A: General   290 ( 1-2 ) 212 - 220  2005.08  [Refereed]

     View Summary

    A disk-type Sm0.4Ba0.6Co0.2Fe 0.8O3 - δ perovskite-type mixed-conducting membrane was applied to a membrane reactor for the partial oxidation of methane to syngas (CO + H2). The reaction was carried out using Rh (1 wt%)/MgO catalyst by feeding CH4 diluted with Ar. While CH4 conversion increased and CO selectivity slightly decreased with increasing temperature, a high level of CH4 conversion (90%) and a high selectivity to CO (98%) were observed at 1173 K. The oxygen flux was increased under the conditions for the catalytic partial oxidation of CH4 compared with that measured when Ar was fed to the permeation side. We investigated the reaction pathways in the membrane reactor using different membrane reactor configurations and different kinds of gas. In the membrane reactor without the catalyst, the oxygen flux was not improved even when CH 4 was fed to the permeation side, whereas the oxygen flux was enhanced when CO or H2 was fed. It is implied that the oxidation of CO and H2 with the surface oxygen on the permeation side improves the oxygen flux through the membrane, and that CO2 and H 2O react with CH4 by reforming reactions to form syngas. © 2005 Elsevier B.V. All rights reserved.

    DOI

  • Hydrogen production via steam-iron reaction using iron oxide modified with very small amounts of palladium and zirconia

    Kohei Urasaki, Naoshi Tanimoto, Taito Hayashi, Yasushi Sekine, Eiichi Kikuchi, Masahiko Matsukata

    Applied Catalysis A: General   288 ( 1-2 ) 143 - 148  2005.07  [Refereed]

     View Summary

    We investigated hydrogen production by the steam-iron reaction using iron oxide modified with very small amounts of palladium and/or zirconia at a temperature of 723 K and under atmospheric pressure. Reduction of iron oxide with hydrogen and oxidation of partially reduced iron oxide with steam (Fe 3O4 + 4H2 ↔ 3Fe + 4H2O) were repeated in the range of reduction degree of 30-50 mol%. Changes in the weight of the samples were monitored using a tapered element oscillating microbalance (TEOM) to control the degree of reduction. Unmodified iron oxide caused significant deactivation due to sintering with increasing number of redox cycles. The addition of a very small amount (0.23 mol%) of palladium or zirconia onto the surface of the iron oxide enhanced the reduction and/or oxidation of the partially reduced iron oxide, which suppressed sintering. Palladium accelerated both the reduction and oxidation rates of partially reduced iron oxide, while zirconia increased only the oxidation rate. Addition of both palladium and zirconia together to the iron oxide resulted in marked enhancement of both reduction and oxidation. © 2005 Elsevier B.V. All rights reserved.

    DOI

  • Catalytic activities and coking resistance of Ni/perovskites in steam reforming of methane

    Kohei Urasaki, Yasushi Sekine, Sho Kawabe, Eiichi Kikuchi, Masahiko Matsukata

    Applied Catalysis A: General   286 ( 1 ) 23 - 29  2005.05  [Refereed]

     View Summary

    Steam reforming of methane for the purpose of hydrogen production was performed using nickel catalysts supported on a variety of perovskites, including LaAlO3, LaFeO3, SrTiO3, BaTiO 3, La0.4Ba0.6Co0.2Fe 0.8O3-8, to compare the catalytic activity and resistance to coking of these catalysts to those of the conventional Ni/α-Al 2O3 catalyst. Ni/LaAlO3 and Ni/SrTiO 3 showed high catalytic activities among the Ni/ perovskites and longer-term stabilities than the conventional catalyst. Temperature programmed oxidation of carbon deposited on used catalysts revealed that inactive carbon species detected on Ni/α-Al2O3 were not formed in the case of Ni/LaAlO3. The results of temperature programmed reduction confirmed that consumption and recovery of the lattice oxygen in perovskites occurred during the reaction, and that the reducibility of perovskites had a great impact on the steam reforming activity. The lattice oxygen in perovskites is considered to play important roles in promoting the oxidation of CH, fragments adsorbed on metallic nickel. © 2005 Published by Elsevier B.V.

    DOI

  • Hydrogen production from biomass-ethanol at ambient temperature with novel diaphragm reactor

    Yasushi Sekine, Shinjiro Asai, Kouhei Urasaki, Masahiko Matsukata, Eiichi Kikuchi, Shigeru Kado, Fumihiro Haga

    Chemistry Letters   34 ( 5 ) 658 - 659  2005.05  [Refereed]

     View Summary

    We used a novel liquid-fuel-reforming system, with a diaphragm and discharge hybrid apparatus that can be operated under ambient temperature and atmospheric pressure, to obtain 50% hydrogen by steam reforming of ethanol with high energy efficiency of up to 95%. Copyright © 2005 The Chemical Society of Japan.

    DOI

  • Hydrogen production by steam reforming of ethanol using cobalt and nickel catalysts supported on strontium titanate

    Kohei Urasaki, Kazuhisa Tokunaga, Yasushi Sekine, Eiichi Kikuchi, Masahiko Matsukata

    Chemistry Letters   34 ( 5 ) 668 - 669  2005.05  [Refereed]

     View Summary

    The steam reforming of ethanol over Co and Ni catalysts supported on SrTiO3 was carried out at 823 K and atmospheric pressure. It was found that Co/SrTiO3 showed a high catalytic activity and long-term stability and remarkably inhibited carbon deposition. Copyright © 2005 The Chemical Society of Japan.

    DOI

  • Improving oxygen permeability in SrFeCo<inf>0.5</inf>O<inf>x</inf> asymmetric membranes by modifying support-layer porous structure

    Masayuki Ikeguchi, Kentaro Ishii, Yasushi Sekine, Eiichi Kikuchi, Masahiko Matsukata

    Materials Letters   59 ( 11 ) 1356 - 1360  2005.05  [Refereed]

     View Summary

    Disk-type SrFeCo0.5Ox asymmetric membranes were prepared for high-temperature oxygen separation using both a previously reported solid state technique in which ethyl cellulose is introduced and then removed by calcination to produce a porous support layer and a modified technique in which carbon fiber is added to the ethyl cellulose. The oxygen permeabilities of the resulting SrFeCo0.5Ox asymmetric membranes were measured at 973-1173 K. The addition of carbon fiber to ethyl cellulose resulted in the improvement of gas diffusivity in the porous support layer, which increased the flux of oxygen through the modified asymmetric membrane. © 2005 Elsevier B.V. All rights reserved.

    DOI

  • Effect of a small amount of zirconia additive on the activity and stability of iron oxide during repeated redox cycles

    Kohei Urasaki, Yasushi Sekine, Naoshi Tanimoto, Eri Tamura, Eiichi Kikuchi, Masahiko Matsukata

    Chemistry Letters   34 ( 2 ) 230 - 231  2005.02  [Refereed]

     View Summary

    Addition of an exceedingly small amount of zirconia onto iron oxide enhanced the activity for hydrogen production by the oxidation of partially reduced iron oxide. Sintering of iron oxide was also suppressed. Copyright © 2005 The Chemical Society of Japan.

    DOI

  • A novel method for hydrogen production from liquid ethanol/water at room temperature

    Yasushi Sekine, Kohei Urasaki, Shinjiro Asai, Masahiko Matsukata, Eiichi Kikuchi, Shigeru Kado

    Chemical Communications   ( 1 ) 78 - 79  2005.01  [Refereed]

     View Summary

    We demonstrated that non-catalytic ethanol steam reforming proceeds efficiently and selectively without coking at the conditions of room temperature and atmospheric pressure using low-energy pulsed (LEP) discharge in combination with carbon fiber electrodes.

    DOI

  • Rapid crystallization of Si-MCM-41 under Na-free conditions

    S. Inagaki, Y. Aratani, Y. Sekine, E. Kikuchi, M. Matsukata

    Studies in Surface Science and Catalysis   158 A   533 - 540  2005  [Refereed]

     View Summary

    Rapid synthesis of Si-MCM-41 was accomplished in successive two steps; (1) aging of a mixture of silica, hexadecylammonium bromide and water with an aqueous ammonia solution for a short period of 30 min, and (2) successive evaporation-to-dryness of the resultant mixture at 80°C in about 2 h. The yield of Si-MCM-41 reached 99% after calcination at 550°C. The product obtained by this method gave a well-ordered 2d-hexagonal structure with high thermal stability and water-resistance. It was noteworthy that the d 100 value of calcined Si-MCM-41 was almost the same as that of as-made Si-MCM-41, suggesting that pore wall of as-made product was dense and rigid. © 2005 Elsevier B.V. All rights reserved.

  • 石炭外表面の親水・疎水度がカラム浮選成績に及ぼす影響

    関根 泰, 佐藤大介, 山口大輔, 菊地英一, 松方正彦

    日本エネルギー学会誌   84   918 - 923  2005

  • メタノール水蒸気改質用アルミナ担持銅亜鉛触媒の開発

    角 茂, 関根 泰, 野崎智洋, 岡崎 健, L.L.Loban, R.G.Mallinson

    化学工業   56 ( 12 ) 6 - 11  2005

  • Solid state synthesis of SrFeCo<inf>0.5</inf>O<inf>x</inf> asymmetric membranes for oxygen separation

    Masayuki Ikeguchi, Yasukazu Uchida, Yasushi Sekine, Eiichi Kikuchi, Masahiko Matsukata

    Journal of Chemical Engineering of Japan   38 ( 7 ) 502 - 508  2005  [Refereed]

     View Summary

    SrFeCo0.5Ox asymmetric membranes for oxygen permeation consisting of a thin dense layer and a porous support layer were prepared using a simple method. A given amount of SrFeCo0.5Ox powder was placed in a die, and then a mixture of SrFeCo0.5Ox powder and ethyl cellulose powder was added on top of the SrFeCo0.5Ox powder. The layered powders were pressed into a 13-mm-diameter disk, and calcined at 1423 K. This produced a membrane with a thin dense layer and, through the elimination of the ethyl cellulose, a porous support layer. Oxygen flux through membranes thus produced increased with decreasing dense-layer thickness. The maximum oxygen flux through an asymmetric membrane at 1173 K observed was 0.23 cm3 (STP) cm-2 min-1, which was 2.8 times larger than that through a 0.95-mm-thick symmetric membrane. Oxygen permeation was primarily limited by bulk diffusion in the thin dense layer, although the porous support layer acted to resist oxygen permeation. Copyright © 2005 The Society of Chemical Engineers, Japan.

    DOI

  • New evaluation method of carbonaceous structure on coal steam gasification

    Yasushi Sekine, Kiyohiro Ishikawa, Eiichi Kikuchi, Masahiko Matsukata

    Energy and Fuels   19 ( 1 ) 326 - 327  2005.01  [Refereed]

     View Summary

    The influence of carbonaceous structural change and ash behavior affecting reactivity was clarified using an analysis method that employs microscopy. Detailed analysis with this method was possible. Furthermore, the effect that ash had on the change of carbonaceous structure was clarified.

    DOI

  • Nonequilibrium pulsed discharge: A novel method for steam reforming of hydrocarbons or alcohols

    Yasushi Sekine, Kohei Urasaki, Shigeru Kado, Masahiko Matsukata, Eiichi Kikuchi

    Energy and Fuels   18 ( 2 ) 455 - 459  2004.03  [Refereed]

     View Summary

    Steam reforming of methane, propane, hexane, cyclohexane, methanol, and ethanol using a nonequilibrium pulsed discharge was investigated under the conditions of atmospheric pressure and low temperature (393 K) without the use of catalyst. In each case, steam reforming proceeded efficiently and selectively and hydrogen was formed as a main product. Although the steam/carbon ratio was 1, there were trace amounts of carbon deposition or wax formation. The energy injection for the discharge region calculated by current and voltage waveforms measured by a digital signal oscilloscope was very small. As compared with the conventional catalytic steam reforming process, this method has some advantages such as fast start-up, quick response, and miniaturization and simplification of a hydrogen production system. Therefore we consider that the hydrogen production system employing a nonequilibrium pulsed discharge has a potential for being an effective way for supplying hydrogen or syngas.

    DOI

  • Diagnosis of atmospheric pressure low temperature plasma and application to high efficient methane conversion

    Shigeru Kado, Yasushi Sekine, Tomohiro Nozaki, Ken Okazaki

    Catalysis Today   89 ( 1-2 ) 47 - 55  2004.02  [Refereed]

     View Summary

    Direct dehydrogenation of methane to produce more useful chemicals was examined using low temperature plasmas such as DBD, corona and spark discharge under the conditions of room temperature and atmospheric pressure. In spark discharge, acetylene was produced with the selectivity higher than 85% and small amount of deposited carbon. The energy efficiency in spark discharge was much higher than that in DBD and corona discharge. By the emission spectroscopy, it was found that methane was highly dissociated to atomic carbon and hydrogen in spark discharge. The gas temperature in spark discharge channel remained as low as 420-460K determined by Boltzmann plot method of CH rotational band (431 nm). The specific energy requirement for acetylene was improved by the optimization of reactor size and residence time and reached 12.1 kWh/kg-C 2H2, which was as same as Huels process with DC arc plasma. © 2003 Elsevier B.V. All rights reserved.

    DOI

  • 放電励起による触媒反応と炭化水素改質への応用

    関根 泰

    ペトロテック   27(10)   802 - 806  2004

  • 高効率メタンプラズマ改質プロセスの開発

    角 茂, 野崎智洋, 岡崎 健, 関根 泰

    触媒   46(3)   242 - 247  2004

  • High performance methane conversion into valuable products with spark discharge at room temperature

    S. Kado, Y. Sekine, K. Urasaki, K. Okazaki, T. Nozaki

    Studies in Surface Science and Catalysis   147   577 - 582  2004  [Refereed]

     View Summary

    Non-catalytic methane activation with spark discharge showed high energy efficiency and high selectivity to acetylene by the collision of electrons possessing high energy enough to dissociate methane into atomic carbon. The application of spark discharge to steam reforming of methane was effective for hydrogen production at low temperature. The selectivity to desired product was improved by the combination with catalyst.

  • Reaction mechanism of methane activation using non-equilibrium pulsed discharge at room temperature

    Shigeru Kado, Kohei Urasaki, Yasushi Sekine, Kaoru Fujimoto, Tomohiro Nozaki, Ken Okazaki

    Fuel   82 ( 18 ) 2291 - 2297  2003.12  [Refereed]

     View Summary

    The reaction mechanism of methane activation using non-equilibrium pulsed discharge was largely clarified from the emission spectroscopic study and experiments with higher hydrocarbons and some kinds of isotopes. The strong emission of atomic carbon and C2 swan band system was observed as well as H Balmer series emission. This indicates that methane was highly dissociated into C and H by electron impact, which is consistent with the result of high C2D2 composition in produced acetylene when the mixture of CH4 and D2 was fed into discharge region. High electron energy contributed to produce atomic carbon directly from methane, and high electron density promoted the dehydrogenation from CH 3, CH2 and CH to produce atomic carbon consecutively. The reason for the high selectivity to C2H2 was the high concentration of CH or C2 formed from atomic carbon, and the repetition mechanism of decomposition and recombination among C, CH, C 2 and C2H2. © 2003 Elsevier Ltd. All rights reserved.

    DOI

  • Direct conversion of methane to acetylene or syngas at room temperature using non-equilibrium pulsed discharge

    Shigeru Kado, Kohei Urasaki, Yasushi Sekine, Kaoru Fujimoto

    Fuel   82 ( 11 ) 1377 - 1385  2003.07  [Refereed]

     View Summary

    Non-catalytic direct conversion of methane to valuable products was studied using non-equilibrium pulsed discharge under the conditions of ambient temperature and atmospheric pressure. Acetylene was produced with 95% selectivity and 52% methane conversion. An addition of oxygen, carbon dioxide and steam contributed significantly to suppress the carbon deposition and produced carbon monoxide as well as acetylene. Methane conversion increased with an increase in the pulse frequency while the product selectivity remained almost constant. The selectivity depended on the composition of the feed gas. The effect of the partial pressure of oxygen was examined, and it was found that the pulsed discharge would be able to produce synthesis gas by partial oxidation of methane. Carbon monoxide selectivity of 79% with methane conversion of 76% was obtained under the conditions of CH4/O2 = 25/25cm3min-1, gap distance of 10mm and the frequency of 45Hz. © 2003 Elsevier Science Ltd. All rights reserved.

    DOI

  • 高エネルギー電子衝突による高効率メタン転換反応

    角 茂, 関根 泰, 野崎 智洋, 岡崎 健

    化学工学会 研究発表講演要旨集   2003   304 - 304  2003

    DOI CiNii

  • 低エネルギー放電を用いた水素製造プロセス

    関根 泰

    機能材料   4   57 - 67  2003

  • 低エネルギーパルス放電を用いた水素製造プロセス

    関根 泰, 松方 正彦, 菊地 英一, 角 茂

    ケミカルエンジニヤリング   12   25 - 33  2003

  • エネルギーの視点から見た2030年の私たちの社会

    関根ら

    日本エネルギー学会誌82   1   2 - 24  2003

  • Methane coupling and reforming using non-equilibrium pulsed discharge at room temperature: Catalyst-pulsed discharge combined system

    S Kado, K Urasaki, H Nakagawa, K Miura, Y Sekine

    UTILIZATION OF GREENHOUSE GASES   852   302 - 313  2003  [Refereed]

     View Summary

    The comparison between DC corona and pulsed discharge was made for the formation of C2 hydrocarbons. Using the corona discharge, the consecutive dehydrogenation from ethane was observed. On the other hand, in the pulsed discharge reaction, acetylene was produced with 95% selectivity independent of methane conversion. In addition, the combination of catalyst and pulsed discharge had a great effect on the selectivity. The use of Ni-catalyst with the pulsed discharge promoted carbon dioxide reforming selectively at room temperature. And the yield of ethane reached 49% by using 1 wt% Pt/SiO2.

  • Hydroisomerization of tetralin on zeolite beta: Influence of crystal size

    Praveen Sharma, Yasutoshi Iguchi, Yasushi Sekine, Eiichi Kikuchi, Masahiko Matsukata

    Studies in Surface Science and Catalysis   145   219 - 222  2003  [Refereed]

     View Summary

    Though light cycle oils (LCO) obtained in the fluid catalytic cracking (FCC) are rich in aromatics and sulphur but are insufficient to diesel fuels due to the low cetane number. It is worthwhile to produce alkylbenzenes from LCO without producing small olefinic hydrocarbons through hydrotreating polyaromatic compounds present in the LCO. In the present study tetralin was used as a model compound. Reactions such as ring opening, dealkylation, transalkylation, hydrogen transfer and coke formation were studied using Platinum-supported beta as catalyst. The objective of this study was to investigate the relationship between the crystal size of beta zeolite and catalytic properties for hydrotreatment of tetralin.

    DOI

  • Direct Conversion of Methane using Non-equilibrium Pulsed Discharge with and without Catalysts

    S.Kado, K.Urasaki, Y.Sekine, K.Fujimoto

    J. Thermal Science & Engineering   11   1 - 8  2003

  • Catalytic degradation of PP with Fe/Activated carbon catalyst

    Y.Sekine, K.Fujimoto

    J.Mat.Cyc.Wast.Manag.   5   107 - 112  2003

  • Methane coupling and reforming using non-equilibrium pulsed discharge at room temperature

    Shigeru Kado, Kohei Urasaki, Yasushi Sekine

    ACS Division of Fuel Chemistry, Preprints   47 ( 1 ) 326 - 327  2002.03  [Refereed]

     View Summary

    Selective formation of C2H2 and/or CO was achieved using a periodic pulsed spark discharge, with and without catalysts, at room temperature. The selective formation of C2H2 with high conversion was achieved. A 49% yield of C2H6 was obtained in Pt/SiO2 and discharge combined system. With the increased of CO2 content, C2 selectivity decreased sharply, while CO selectivity increased drastically. Under the condition of high CH4 concentration, the formation of C2H2 was predominant whereas under the condition of high CO2 concentration, CO became the main product. The use of pretreated NiMgO solid solution catalyst increased CO selectivity to 85% at CH4/CO2 = 1:1, while no remarkable effect was observed without pretreated catalysts. The pulsed spark discharge reaction of CH4 in the presence of O2 produced CO and C2H2 at room temperature while suppressing carbon deposition and CO2 formation.

  • Methane Reforming with Carbon Dioxide and Oxygen under Atmospheric and Pressurized Conditions Using Fixed- and Fluidized-Bed Reactors

    Keiichi Tomishige, Yuichi Matsuo, Mohammad Asadullah, Yusuke Yoshinaga, Yasushi Sekine, Kaoru Fujimoto

    ACS Symposium Series   809   303 - 315  2002  [Refereed]

     View Summary

    Effect of the reactor in methane reforming with carbon dioxide and oxygen over NiO-MgO catalysts under atmospheric and pressurized conditions was investigated. Under atmospheric pressure, the stable activity was observed using the fluidized bed reactor. However, in the fixed bed reactor, the activity decreased gradually with time on stream. On the other hand, at low temperature and high space velocity, methane conversion decreased rapidly to the level of methane combustion using fluidized bed reactor. Under pressurized condition, the stable production of syngas was possible even at high space velocity since the catalyst is in more reducing atmosphere at higher pressure. The fluidized bed reactor enhanced more effective conversion of methane to syngas than the fixed bed reactor.

    DOI

  • Comparative study between fluidized bed and fixed bed reactors in methane reforming combined with methane combustion for the internal heat supply under pressurized condition

    Keiichi Tomishige, Yuichi Matsuo, Yusuke Yoshinaga, Yasushi Sekine, Mohammad Asadullah, Kaoru Fujimoto

    Applied Catalysis A: General   223 ( 1-2 ) 225 - 238  2002  [Refereed]

     View Summary

    The effect of catalyst fluidization on the conversion of methane to syngas in methane reforming with CO2 and H2O in the presence of O2 under pressurized conditions was investigated over Ni and Pt catalysts. Methane and CO2 conversion in the fluidized bed reactor was higher than those in the fixed bed reactor over Ni0.15Mg0.85O catalyst under 1.0 MPa. This reactor effect was dependent on the catalyst properties. Conversion levels in the fluidized and fixed bed reactor were almost the same over MgO-supported Ni and Pt catalysts. It is suggested that this phenomenon is related to the catalyst reducibility. On a catalyst with suitable reducibility, the oxidized catalyst can be reduced with the produced syngas and the reforming activity regenerates in the fluidized bed reactor. Although serious carbon deposition was observed on Ni0.15Mg0.85O in the fixed bed reactor, it was inhibited in the fluidized bed reactor. © 2002 Elsevier Science B.V. All rights reserved.

    DOI

  • Low temperature reforming of methane to synthesis gas with direct current pulse discharge method

    S. Kado, K. Urasaki, Y. Sekine, K. Fujimoto

    Chemical Communications   ( 5 ) 415 - 416  2001.03  [Refereed]

     View Summary

    Synthesis gas was produced by pulsed irradiation of electrons on a mixture of CH4 and CO2 (or H2O) at low temperature and atmospheric pressure without catalysts; especially in the CO2 reforming reaction, the H2 : CO ratio could be controlled and depended on the concentration of CO2 in the feed gas.

    DOI

  • これからのプラスチックリサイクルのあり方は?ーポリオレフィン系プラスチックのリサイクルについて考える

    関根 泰

    化学と工業   12   1352 - 1355  2001

  • Direct synthesis of acetylene from methane by direct current pulse discharge

    Shigeru Kado, Yasushi Sekine, Kaoru Fujimoto

    Chemical Communications   2485 ( 24 ) 2485 - 2486  1999.12  [Refereed]

     View Summary

    In non-catalytic direct conversion of methane to acetylene by using direct current pulse discharge under conditions of ambient temperature and atmospheric pressure, the selectivity of acetylene from methane was >95% at methane conversion ranging from 16 to 52%; coexisting oxygen was very effective in removing deposited carbon and stabilized the state of discharge.

    DOI

  • Reaction control in radical-transforming catalytic degradation of polypropylene

    Keio Kato, Tomohiro Kamimura, Yasushi Sekine, Kaoru Fujimoto

    Sekiyu Gakkaishi (Journal of the Japan Petroleum Institute)   42 ( 4 ) 222 - 227  1999.07  [Refereed]

     View Summary

    For the purpose of chemical recycling of plastic wastes, catalytic degradation and liquefaction of Polypropylene (PP). subjected to high pressure H2 was examined with a batch reactor. Iron supported active carbon (Fe/A.C.) acted to decrease solids and also increase liquid yield in condition of 673-693 K at H2 pressure of 4.0 MPa (NTP) for 1 h. Compared with thermal degradation, liquid products became lighter because residue produced was degradated by the catalyst. Compared H2 with Ar as reaction gas at 683 K, degradation of PP was promoted by H2 in 0.5-1.0 h. In the results of the effect of H2 pressure, degradation of PP was proceeded as the increase of H2 under 3.0 MPa but was suppressed over 4.0 MPa. These results show that H2 plays an important role in catalytic degradation of PP over Fe/A.C. catalyst.

    DOI

  • New method for direct conversion of methane

    Y. Sekine, K. Fujimoto

    Kinetics and Catalysis   40 ( 3 ) 294 - 300  1999.05  [Refereed]

     View Summary

    Methane was oxidized by oxygen in the absence of a catalyst with the microwire initiation (MWI) method, which was composed of an electrically heated small wire and a low-temperature reaction zone. With the existence of initiation reaction, methanol and carbon monoxide were formed at 393 K gas phase temperature. The main products of the reaction were methanol, hydrogen, carbon monoxide, carbon dioxide, and water. With the batch-wise MWI system, methanol selectivity was higher than 80% at the initial stage of the reaction. In the absence of MWI, no products were formed under 653 K of gas phase temperature in the chain reaction zone. We proposed a new model for the oxidation of methane with microwire initiation.

  • Partial oxidation of methane with micro wire initiation under normal pressures

    Shigeru Kado, Yasushi Sekine, Kaoru Fujimoto

    Sekiyu Gakkaishi (Journal of the Japan Petroleum Institute)   41 ( 4 ) 295 - 296  1998  [Refereed]

     View Summary

    The method of micro wire initiation(MWI) was applied to partial oxidation of methane under normal pressures. Consequently, the formation of acetone was identified besides CO, CO2, C2, hydrogen and methanol. Under the condition that the temperature of filament surface was low and gas phase was high, the selectivity of acetone was 67 %. It was proved that the selective conversion of methane to oxygen-containing compounds can proceed directly with the MWI method.

    DOI

  • Oxidative coupling of methane in the gas phase: Simulation and reaction mechanism

    Y. Sekine, T. Nishimura, K. Fujimoto

    Energy and Fuels   12 ( 4 ) 828 - 829  1998  [Refereed]

    DOI

  • Direct conversion of methane to methanol with Micro Wire Initiation (MWI)

    Y. Sekine, K. Fujimoto

    Studies in Surface Science and Catalysis   119   277 - 282  1998  [Refereed]

     View Summary

    Methane is oxidized by oxygen in the absence of catalyst with micro wire initiation (MWI; the concept is shown in Fig. 1) method, which is composed of electrically heated small wire and low temperature reaction zone. With the existence of initiation reaction, methanol and CO was formed even under 400 K gas phase temperature. Main products of the reaction were methanol, hydrogen, CO, CO2 and water. We claimed a new model for the oxidation of methane with MWI. © 1998 Elsevier Science B.V. All rights reserved.

    DOI

  • Initiation-chain reaction separated oxidation of gas phase methane

    Yasushi Sekine, Kaoru Fujimoto

    Sekiyu Gakkaishi (Journal of the Japan Petroleum Institute)   41 ( 4 ) 269 - 270  1998  [Refereed]

     View Summary

    Although the chemical utilization of methane has been considered promising highly, the majority of uses are via the reforming of methane to synthesis gas, which is attributed to the high stability of methane. In this study, the authors tried to keep separate the location of the initial activation of methane at high temperature and that of the consecutive chain reaction at low temperature. A method of MWI (abbreviation of Micro Wire Initiation) activates the methane molecule and the activated species are smoothly introduced into the tandem chain reaction zone, which is connected downstream of the initiation zone. In the MWI system, methanol was formed at 393 K and its selectivity increased as increasing in total pressure. No reaction proceeded without MWI below 683 K, and there are no obvious differences in either methane conversion or product distribution for different reaction temperatures. Over 683 K, the conversion of methane and the selectivity to methanol increased with reaction temperatures. The selectivity to methanol depends on the reaction pressure. Low total pressure favors the formation of CO. It is important to note that if methyl radical is produced by MWI activation, successive chain reaction could proceed at temperature as low as 393 K.

    DOI

  • Low temperature direct oxidation of methane to methanol

    Kaoru Fujimoto, Yasushi Sekine

    Studies in Surface Science and Catalysis   107   63 - 66  1997  [Refereed]

     View Summary

    Methane was oxidized by oxygen at temperatures as low as 473K or lower under pressurized conditions. The reaction was initialed by heated wire, which was set in the center of a pressurized reaction chamber. At the initial stage of the reaction, the methanol selectivity was as high as 90%, but its level decreased quickly with proceeding of the reaction time. When the reaction pressure was raised from 5 to 40atm, the methanol selectivity (at high O2 conversion level) was increased from 2% to 30% whereas selectivities of C2 hydrocarbons of CO2 decreased 30% to 10% or less. A new reaction model was claimed for the present reaction system. © 1997 Elsevier Science B.V. All rights reserved.

  • Low-temperature direct conversion of methane to methanol with filament wire initiation method

    Yasushi Sekine, Kaoru Fujimoto

    Energy and Fuels   10 ( 6 ) 1278 - 1279  1996  [Refereed]

    DOI

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Books and Other Publications

  • 天然ガス資源とその応用技術

    関根 泰

    シーエムシー出版  2008

  • メタン高度化学変換技術集成

    関根 泰

    シーエムシー出版  2008

  • トコトンやさしい触媒の本

    関根 泰

    日刊工業新聞社刊  2007

  • プラスチック化学再資源化技術

    関根 泰

    シーエムシー出版  2005

  • 実験化学講座5高圧装置

    関根 泰(共, 担執筆

    丸善  2005

  • 水素利用技術集成

    関根 泰(共, 担執筆

    NTS  2003

  • 天然ガスの高度利用技術

    関根 泰

    NTS  2001

▼display all

Misc

  • Effects of alloying for steam or dry reforming of methane: a review of recent studies

    Maki Torimoto, Yasushi Sekine

    Catalysis Science and Technology    2022

    Book review, literature introduction, etc.  

     View Summary

    Methane is an important chemical resource, not only in natural gas but also in biogas, which can be regarded as a renewable energy resource. Reforming of methane with steam or carbon dioxide, which is important for producing hydrogen and syngas, is conducted at high temperatures using heterogeneous catalysts. To achieve high activity, stability, and low carbon deposition, many studies have been conducted in recent years on the use of alloys as active sites in these catalysts. This review presents a summary of recent studies of alloy catalysts, for which various secondary metals have been added to active metals, such as Ni. Then we summarize the current status of these alloys in terms of their structure, electronic state, and adsorption. The reported effects of alloying include improvement of dispersion and reducibility of the supported metal, change in catalytic performance such as activity and selectivity, and improvement of durability against carbon deposition, sulphur poisoning, and sintering. The directions of future research and development are summarized in terms of sulphur resistance, sintering inhibition, and high activity at low temperatures.

    DOI

  • Enhanced activity of catalysts on substrates with surface protonic current in an electrical field-a review

    Yudai Hisai, Quanbao Ma, Thomas Qureishy, Takeshi Watanabe, Takuma Higo, Truls Norby, Yasushi Sekine

    Chemical Communications   57 ( 47 ) 5737 - 5749  2021.06

    Book review, literature introduction, etc.  

     View Summary

    <p>Schematic reaction mechanisms; (A) without an applied electric field, (B) with an applied electric field.</p>

    DOI PubMed

  • Advanced approaches: General discussion

    Megha Anand, Andrew M. Beale, Mercedes Boronat, M. Bowker, Aram L. Bugaev, Valerii I. Bukhtiyarov, C. Richard A. Catlow, Sarayute Chansai, Michael Claeys, Matthew Conway, Philip R. Davies, Jennifer Edwards, Joseph El-Kadi, Dmitry Eremin, Nico Fischer, Shaoliang Guan, Justin S.J. Hargreaves, Christian Hess, Graham J. Hutchings, Froze Jameel, Ali Reza Kamali, Simon Kondrat, Naomi Lawes, David Lennon, Diyuan Li, Patrick Morgan, Andrea M. Oyarzun Aravena, Christian Reece, Romain Reocreux, Peter W. Seavill, Yasushi Sekine, Mzamo Shozi, Ian Silverwood, Mikhail Sinev, Collin Smith, Michail Stamatakis, Laura Torrente Murciano, Deniz Uner, Bert M. Weckhuysen, Keith Whiston, Moritz Wolf, Bo Yang, Constantinos D. Zeinalipour-Yazdi

    Faraday Discussions   229   378 - 421  2021.02

    Rapid communication, short report, research note, etc. (scientific journal)  

    DOI PubMed

  • Ru/ペロブスカイト触媒における担体組成の電場アンモニア合成への影響

    土井咲英, 田中雄太, 村上洸太, 伊東一陽, 水谷優太, 七種紘規, 比護拓馬, 常木英昭, 関根泰

    触媒討論会講演予稿集(CD-ROM)   127th  2021

    J-GLOBAL

  • CeO2への異種カチオンドープによる担持Fe凝集抑制

    三瓶大志, 村上洸太, 水谷優太, 石川敦之, 比護拓馬, 常木英昭, 中井浩巳, 関根泰

    触媒討論会討論会A予稿集(CD-ROM)   126th  2020

    J-GLOBAL

  • 電場印加時のメタン水蒸気改質におけるCeO2担体へのAlドープ効果

    高橋綾子, 稲垣玲於奈, 鳥本万貴, 久井雄大, 松田卓, SEO Jeong Gil, MA Quanbao, 比護拓馬, 常木英昭, 小河脩平, NORBY Truls, 関根泰

    触媒討論会討論会A予稿集(CD-ROM)   126th  2020

    J-GLOBAL

  • 電場触媒反応における担体上でのプロトン濃度の影響

    土井咲英, 田中雄太, 村上洸太, 比護拓馬, 小河脩平, 小河脩平, SEO Jeong Gil, 常木英昭, 関根泰

    石油・石油化学討論会講演要旨   50th (Web)  2020

    J-GLOBAL

  • 電場中での低温メタン水蒸気改質反応における担体の構造の影響

    永川華帆, 高橋綾子, 稲垣玲於奈, 鳥本万貴, 久井雄大, 松田卓, SEO Jeong Gil, 比護拓馬, 常木英昭, 小河脩平, 小河脩平, NORBY Truls, 関根泰

    石油・石油化学討論会講演要旨   50th (Web)  2020

    J-GLOBAL

  • Ba添加ペロブスカイト型触媒におけるエタン脱水素反応の理論的検討

    七種紘規, 伊東一陽, 都甲健太, 村上洸太, 斎藤晃, 小河脩平, 常木英昭, 前田駿, 橋本国秀, 関根泰

    石油・石油化学討論会講演要旨   50th (Web)  2020

    J-GLOBAL

  • Fe系触媒を用いた電場アンモニア合成

    水谷優太, 堺竜哉, 村上洸太, 小河脩平, 萩庭尚道, 常木英昭, 関根泰

    触媒討論会講演予稿集(CD-ROM)   125th  2020

    J-GLOBAL

  • 低温電場中でのCePO4触媒を用いたメタン酸化カップリング

    竹野友菜, 小河脩平, 小河脩平, 佐藤綾香, 比護拓馬, 常木英昭, 鎌田慶吾, 鎌田慶吾, 原亨和, 関根泰

    触媒討論会講演予稿集(CD-ROM)   125th  2020

    J-GLOBAL

  • 低温電場反応場でのメタン水蒸気改質におけるCeO2へのAlドープ効果

    高橋綾子, 鳥本万貴, 稲垣玲於奈, 久井雄大, 松田卓, 竹野友菜, 比護拓馬, 常木英昭, 小河脩平, MA Quanbao, NORBY Truls, 関根泰

    触媒討論会講演予稿集(CD-ROM)   125th  2020

    J-GLOBAL

  • 電場を用いたアンモニア合成における卑金属触媒の探索

    田中雄太, 村上洸太, 堺竜哉, 都甲健太, 伊東一陽, 石川敦之, 比護拓馬, 矢部智宏, 小河脩平, 池田昌稔, 常木英昭, 常木英昭, 中井浩巳, 関根泰

    触媒討論会講演予稿集(CD-ROM)   123rd  2019

    J-GLOBAL

  • 電場アンモニア合成活性の特異な温度依存性

    田中雄太, 村上洸太, 堺竜哉, 久井雄大, 比護拓馬, 小河脩平, 池田昌稔, 常木英昭, 常木英昭, SEO Jeong Gil, 関根泰

    石油学会年会講演要旨   62nd  2019

    J-GLOBAL

  • 電場アンモニア合成におけるSrZrO3担体へのドープ効果

    田中雄太, 村上洸太, 林流石, 堺竜哉, 石川敦之, 小河脩平, 常木英昭, 萩庭尚道, 中井浩巳, 関根泰

    触媒討論会討論会A予稿集(CD-ROM)   124th  2019

    J-GLOBAL

  • 低温電場中でのLa-Ca-Al-O系ペロブスカイト型酸化物を用いたメタン酸化カップリング

    竹野友菜, 小河脩平, 小河脩平, 佐藤綾香, 瀧瀬賢人, 常木英昭, SEO Jeong Gil, 関根泰

    触媒討論会討論会A予稿集(CD-ROM)   124th  2019

    J-GLOBAL

  • 低温域における表面プロトン伝導の発現とアンモニア合成反応の促進

    田中雄太, 村上洸太, 真鍋亮, 上手裕紀子, 久井雄大, 小河脩平, 常木英昭, 池田昌稔, TRULS Norby, 関根泰

    触媒討論会討論会A予稿集   122nd  2018

    J-GLOBAL

  • 表面プロトン伝導を用いたアンモニア合成の反応メカニズム

    村上洸汰, 中坪秀彰, 真鍋亮, 上手裕紀子, 久井雄大, 小河脩平, 常木英昭, 池田昌稔, 石川敦之, 中井浩巳, TRULS Norby, 関根泰

    触媒討論会討論会A予稿集   122nd  2018

    J-GLOBAL

  • 表面プロトン伝導を用いたアンモニア合成

    村上洸太, 中坪秀彰, 真鍋亮, 上手裕紀子, 久井雄大, 小河脩平, 常木英昭, 池田昌稔, 石川敦之, 中井浩巳, NORBY Truls, 関根泰

    固体イオニクス討論会講演要旨集   44th  2018

    J-GLOBAL

  • 電場印加によるアンモニア合成促進効果の検討

    村上洸太, 中坪秀彰, 真鍋亮, 小河脩平, 常木英昭, 池田昌稔, 関根泰

    触媒討論会講演予稿集   119th  2017

    J-GLOBAL

  • 電場印加触媒反応を用いたRu担持触媒による低温アンモニア合成の速度論的検討

    権東阿美, 中坪秀彰, 真鍋亮, 小河脩平, 常木英昭, 池田昌稔, 関根泰

    石油学会年会講演要旨   59th  2016

    J-GLOBAL

  • 低温における電場触媒反応を用いたRu担持触媒によるアンモニア合成

    村上洸太, 中坪秀彰, 真鍋亮, 小河脩平, 常木秀昭, 池田昌稔, 関根泰

    石油・石油化学討論会講演要旨   46th  2016

    J-GLOBAL

  • Pt担持グラフェン構造体触媒によるグルコースからC4オレフィンへの転換反応

    務川慧, 大山永展, 新見隼隆, 関根輝, 恩田歩武, 小河脩平, 関根泰

    触媒   58   61 - 63  2016

  • Oxidative Coupling of Methane

      44 ( 8 ) 14 - 18  2015.08

    CiNii

  • Catalytic methane steam reforming in an electric field at low temperature

    Ryo Manabe, Kazumasa Oshima, Yusuke Sasaki, Shuhei Ogo, Yasushi Sekine

    ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY   248  2014.08

    Research paper, summary (international conference)  

  • Role of interface between metal and support on steam reforming of toluene over Ni/LSAO-perovskite catalyst

    Daiki Mukai, Kento Takise, Masaya Imori, Shuhei Ogo, Yukihiro Sugiura, Yasushi Sekine

    ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY   248  2014.08

    Research paper, summary (international conference)  

  • Steam reforming of ethanol over Co/K/a-Al2O3 catalyst

    Shuhei Ogo, Takuya Shimizu, Yusaku Nakazawa, Kei Mukawa, Daiki Mukai, Yasushi Sekine

    ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY   248  2014.08

    Research paper, summary (international conference)  

  • Synthesis of structured carbon particles in an electric field and its application

    Kei Mukawa, Naganobu Oyama, Hiroaki Ando, Takashi Sugiyama, Shuhei Ogo, Yasushi Sekine

    ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY   248  2014.08

    Research paper, summary (international conference)  

  • Microporous membrane: A key to large-scale energy-saving in fuel and petrochemical industry

    Masahiko Matsukata, Yasushi Sekine, Eiichi Kikuchi

    ACS National Meeting Book of Abstracts   242  2011  [Refereed]

     View Summary

    Reducing energy consumption on the industry sector has increasingly been a strong request to mitigate CO 2 problem. In particular, in chemical industry about 40% of the total energy is consumed for separation in which 90% or more is used for distillation. Zeolites have superior physicochemical properties, such as molecular sieving and preferential adsorption, in addition to high thermal, chemical, and structural stability. Therefore, researchers have been motivated to apply them as membranes and membrane reactors. In this presentation, we would like to emphasize that R&D of microporous membrane, especially zeolite membrane, is a vital approach for large-scale reduction of energy consumption for separation in petrochemical industry. Two examples will be introduced: acetic acid dehydration through mordenite-type zeolite membrane and silicalite-1 membrane for xylene isomers separation.

  • Fe doped La<inf>2</inf>O<inf>3</inf> catalyst for oxidative coupling of methane

    Keisuke Tanaka, Yasushi Sekine, Masahiko Matsukata, Eiichi Kikuchi

    ACS National Meeting Book of Abstracts   239  2010  [Refereed]

     View Summary

    We examined several metal-doped La2O3 catalysts for OCM reaction. Among them, the Fe-doped La2O3 catalyst indicated good potential for OCM reaction for high O2 conversion and high C2 selectivity. This catalyst was composed of mixture phases of LaFeO3 and La2O3. LaFeO3 related to O2 activation, and La2O3 was associated with C2 generation. The La/Fe ratio on the catalyst affected the C2 yield, changing the balance of LaFeO3 and La2O3 in the catalyst. At La/Fe=20, Fe-doped La2O3 catalyst exhibited the highest C2 yield due to the most effective balance of these two phases.

  • Steam reforming of ethanol over supported iron-cobalt catalyst

    Yasushi Sekine, Atsushi Kazama, Yoshiyuki Izutsu, Masahiko Matsukata, Eiichi Kikuchi

    ACS National Meeting Book of Abstracts   238  2009  [Refereed]

     View Summary

    Biomass is an important energy resource in terms of renewable resource and carbon neutral material. Fermented organic compounds to obtain ethanol include high concentration of water and low concentration of ethanol. Such biomass ethanol has to be distilled with an enormous amount of energy consumption before adding it into gasoline. A new approach to use biomass ethanol with water is hydrogen production by steam reforming of ethanol without distillation. We found that Co/SrTiO3 and Co/alumina catalyst had high activity for steam reforming of ethanol at 823 K. Also we investigated the reaction path from ethanol to hydrogen, promoting effect of small amount of Fe. As a result, we found that an addition of small amount of iron onto the Co catalyst promoted the steam reforming of acetaldehyde to produce hydrogen and CO, CO2.

  • Ultralow temperature steam reforming of methane with novel catalytic system in an electric field

    Yasushi Sekine, Masahiko Tomioka, Masayuki Haraguchi, Masahiko Matsukata, Eiichi Kikuchi

    ACS National Meeting Book of Abstracts   238  2009  [Refereed]

     View Summary

    We investigated novel catalytic reaction system which was activated by an electric field. These catalytic systems showed very high activity compared to conventional catalytic reaction systems, and it works at ultra-low temperature. As for the steam reforming of methane, although Pt supported on CeO2 catalyst without an electric field showed no activity at 423 K, the addition of an electric field to the catalyst promoted the reaction, and higher conversion of methane was observed at the same temperature. Pt/CeO2 catalyst was activated by the electric field and synergetic effect of Pt catalyst and electric field was observed. All the carbon atoms reacted were converted into carbon dioxide via water gas shift. At such low temperature, thermodynamic equilibrium is far from such high methane conversion. Catalytic reactions in an electric field proceed under mild conditions and show a quick response. This novel hybrid system seems to be a promising fuel processing catalytic system at low temperature.

  • FUEL 56-Effective utilization of electrical discharges for hydrogen production

    Yasushi Sekine, Masahiko Matsukata, Elichi Kikuchi

    ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY   235  2008.04

    Research paper, summary (international conference)  

  • Catalyst preparation for vapor phase Beckmann rearrangement via deboronation/desilication of B-ZSM-5

    Masahiko Matsukata, Kohsuke Nakagawa, Yasushi Sekine, Eiichi Kikuchi

    ACS National Meeting Book of Abstracts   235  2008  [Refereed]

     View Summary

    Vapor phase Beckmann rearrangement of cyclohexanone oxime to ε-caprolactam is an outstanding achievement of green chemistry. Nest silanols in the vicinity of the external surface of silicalite-1 has been proposed as active sites. In this study, B-ZSM-5(Si/B ratio = 25) was synthesized and the product was agglomerates of nanocrystals. As-made B-ZSM-5 was calcined in air and deboronated by treatment with HCl aq. at 353 K for 3 h. Further, the deboronated sample was desilicated with a mixture of ammonia nitrate and ammonia to develop effective diffusion pathways in the catalyst particles. FT-IR study confirmed the formation of abundant nest silanols. The vapor phase Backmann reaggrangement was performed in a plug flow reactor with a fixed bed of catalyst at WHSV = 8 h-1 and 653 K. The initial catalytic activity was greatly improved by the treatment performed in this study: The pseudo-first-order reaction constant for the parent B-ZSM-5 was 1.8×10-3 s-1, but that for the deboronated/desilicated ZSM-5 was 0.13 s-1.

  • Mechanistic study of methanol/water/hydrogen separation through ZSM-5 membrane

    Masahiko Matsukata, Kenichi Sawamura, Teruaki Izumi, Mitsuko Takada, Yasushi Sekine, Tetsu Osuna, Eiichi Kikuchi

    ACS National Meeting Book of Abstracts   234  2007  [Refereed]

     View Summary

    In this communication, we will report our recent results on the mechanism of selective permeation of steam and methanol from gas mixtures through ZSM-5 membrane. ZSM-5 membrane was prepared on the outer surface of a porous alpha-alumina tubular support by a secondary-growth method. Based on the results of structural characterization using FE-SEM, TEM, etc., ZSM-5 crystals tightly connected with each other in the absence of amorphous phase. ZSM-5 membrane was highly selective to steam and methanol, and hydrogen was retained in the permeation side at temperatures ranging from 150 to 300°C. Permeation and adsorption experimental results suggested that strong adsorption of water and methanol on Na cation occluded in the micropore of ZSM-5 contributed to the appearance of selective permeation. Such separation properties would be promising for membrane extractor in reactions such as Fischer-Tropsch synthesis and methanol synthesis.

  • Synthesis and Crystallization Mechanism of Zeolite Using Dry Gel Conversion Technique

    MATSUKATA Masahiko, INAGAKI Satoshi, SEKINE Yasushi, KIKUCHI Eiichi

    Catalysts & Catalysis   49 ( 7 ) 579 - 584  2007

    Article, review, commentary, editorial, etc. (other)  

    CiNii

  • Simultaneous dry reforming and desulfurization of biomethane with nonequilibrium discharge at ambient temperature

    Yasushi Sekine, Junya Yamadera, Eiichi Kikuchi, Masahiko Matsukata

    ACS National Meeting Book of Abstracts   232  2006  [Refereed]

     View Summary

    Simultaneous dry reforming and desulfurization of biogas (biomethane) was investigated with a non-equilibrium pulsed discharge at ambient temperature and atmospheric pressure. We found that this system enables to reform biogas without pre-desulfurization, and showed very high energy efficiency. Synthesis gas with the ratio of 1:1 (methane:carbon monoxide) was obtained, and also, hydrogen sulfide was converted into carbon disulfide at the condition of lower methane conversion, and further reaction of carbon disulfide to solid sulfur could be achieved at the condition of higher conversion with a non-equilibrium discharge.

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Industrial Property Rights

  • 製鉄所副生ガスの改質装置及び改質方法

    関根 泰

    Patent

  • 脱水素触媒、脱水素触媒の製造方法、脱水素反応器、脱水素反応器の製造方法、水素の製造システム、及び水素の製造方法

    関根 泰

    Patent

  • 水素製造用触媒、その製造方法及び燃料電池システム

    関根 泰

    Patent

  • 水素製造用触媒、その製造方法及び燃料電池システム

    関根 泰

    Patent

  • 排気ガス浄化装置

    関根 泰

    Patent

  • 燃料改質供給システム

    関根 泰

    Patent

  • 排気ガス浄化システム

    5693110

    関根 泰

    Patent

  • 降伏応力測定法

    4733159

    浅川 基男, 凌 霄, 大西 健太, 関根 泰

    Patent

  • 13C標識ベンゼンの製造方法及び13C標識ベンゼン誘導体

    清水 功雄, 関根 泰, 栗下 晴人, 清水 勇佑, 新関 一馬, 中島 隆行, 木下 純一, 小林 翔一郎

    Patent

  • レドックス能の高いアルキル芳香族化合物の脱水素触媒およびその製造方法並びにそれを使用した脱水素化方法

    5628039

    関根 泰, 菊地 英一

    Patent

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Awards

  • Fellow of RSC

    2021.03   Royal Society of Chemistry  

  • The Commendation for Science and Technology by the Minister of Education, Culture, Sports, Science and Technology

    2020.04   MEXT  

  • 日本化学会 学術賞

    2019.01  

  • 石油学会 論文賞

    2018.02  

  • 石油学会 論文賞

    2015  

  • 日本エネルギー学会 進歩賞

    2010  

  • FSRJ 研究進歩賞

    2009  

  • 触媒学会 奨励賞

    2008.03  

  • 石油学会 奨励賞

    2006.02  

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Research Projects

  • 電場中での表面プロトニクスが拓く新規低温触媒プロセスの学理と応用

    日本学術振興会  科学研究費助成事業 基盤研究(A)

    Project Year :

    2017.04
    -
    2022.03
     

    関根 泰

     View Summary

    メタン水蒸気改質は水素を製造するための重要なプロセスである。表面プロトニクスを半導体担体触媒に適用した場合、メタン水蒸気改質が非常に低い温度で進むことを見出してきた。昨年までの反応機構の解析により、電場により担体表面をプロトンが伝導し(表面プロトニクス)、伝導したプロトンと担持金属上に吸着したメタンが衝突することで反応を促進することが分かった。CH4のC-H結合の活性化を担うのは活性点である金属原子であり、様々な系において合金触媒が反応性、選択性、安定性など様々な面において優位性を示す報告が多い。そこでPd-Zn合金を用い、Ligand効果やEnsemble効果といった合金の効果が電場中活性に与える影響について検討した。結果、律速段階であるCH4の活性化過程は、SR(加熱)ではPd表面で起こり、ER(電場印加)ではPd担体の界面で起こるため、合金化の影響は全く異なり、ZnがPdの活性を向上させるのは電場中のみであることが分かった。XRDおよびEXAFSにより担持金属の構造を、DRIFTS測定によりPd電子状態を検討した結果、Zn添加量が増える程Znからの電子遷移によりPdは電子リッチになり(Ligand効果)、Pd-Pdアンサンブルは減少した(Ensemble効果)。SRではCH4の活性化にはまとまったPdアンサンブルが必要であり、Zn添加によりPd-Pdアンサンブルが減少することで、SR活性が減少した。一方、ERでは、Znに囲まれたPd原子は電場中ではCH4を活性化することが可能であり、Pd-Pdアンサンブルの減少はER活性の低下を起こさず、むしろ、Ligand効果により活性が向上した。これにより、一般的に知られる第二金属の添加における“合金触媒のジレンマ”は、電場という特殊な反応場を用いる事で解決可能になる、という新たなコンセプトを提案できた。

  • Hydrogen Production by Non-Faradaic catalytic reaction at low temperature

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (B)

    Project Year :

    2014.04
    -
    2017.03
     

    SEKINE YASUSHI

     View Summary

    We found that catalytic reactions can be promoted by application of an electric field using a semiconductor support even at low temperature. In order to investigate the proton conduction which is considered to be occurring during the application of electric field, we observed the catalyst surface directly by operando FT - IR, and monitored the conductivity of the surface by the AC impedance method. Apparent activation activation energy was calculated and conduction mechanism was investigated. As a result, it was found that dissociative adsorption of methane was promoted in improving the activity of methane steam reforming by applying an electric field. In addition, as a result of the test using isotope, the inverse isotope effect was observed, and it became clear that dissociation of CH4 is proceeded by a novel reaction mechanism.

  • Fundamental research and application of catalytic reactions in an electric field

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (B)

    Project Year :

    2010.04
    -
    2014.03
     

    SEKINE YASUSHI

     View Summary

    To realize upcoming hydrogen generation, novel method for hydrogen production is required. Now, steam reforming of hydrocarbon is an option for hydrogen production for oil refinery and ammonia synthesis. These high temperature processes cause carbon accumulation on the catalyst due to the catalytic nature. We have revealed that steam reforming of methane proceeds even at 150 degree-C by applying electric field on to Pt/ceria catalyst. The system enabled highly efficient hydrogen production which exhibited very high electron efficiency, thanks to its nature on the midway of catalytic system and electrochemistry.

  • Fundamental research and application of catalytic reactions in an electric field

    Project Year :

    2010
    -
    2013
     

     View Summary

    To realize upcoming hydrogen generation, novel method for hydrogen production is required. Now, steam reforming of hydrocarbon is an option for hydrogen production for oil refinery and ammonia synthesis. These high temperature processes cause carbon accumulation on the catalyst due to the catalytic nature. We have revealed that steam reforming of methane proceeds even at 150 degree-C by applying electric field on to Pt/ceria catalyst. The system enabled highly efficient hydrogen production which exhibited very high electron efficiency, thanks to its nature on the midway of catalytic system and electrochemistry.

  • Development of membrane reactor using microporous membrane

    Project Year :

    2007
    -
    2009
     

     View Summary

    Since conventional energy saving methods are almost mature, further improvement of efficiency requires development of a process based on a novel principal. In this study, we developed an innovative reaction and separation system, or membrane reactor, combining solid catalyst and separation membrane. In particular, we developed a fundamental technology of highly stable microporous membranes for improving stability and permeation and separation performance of separation membrane, which was one of prime tasks for improving performance of membrane reactor. As a result, we succeeded in a development of a novel microporous membrane with stability and permeation and separation performance highly outweighing conventional separation membranes.

  • Catalytic reaction over oxide catalysts with an electric field at ambient temperature and atmospheric pressure

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (B)

    Project Year :

    2006
    -
    2009
     

    SEKINE Yasushi, KIKUCHI Eiichi, MATSUKATA Masahiko

     View Summary

    We investigated synergetic effects of hybridization of electric field (or plasma) and catalyst. We found that catalytic reactions in plasma proceeded very effectively at ambient temperature, and catalytic reactions in an electric field promoted steam reforming of methane at very low temperature like as 423K.

  • Catalytic reaction over oxide catalysts with an electric field at ambient temperature and atmospheric pressure

    Project Year :

    2006
    -
    2009
     

     View Summary

    We investigated synergetic effects of hybridization of electric field (or plasma) and catalyst. We found that catalytic reactions in plasma proceeded very effectively at ambient temperature, and catalytic reactions in an electric field promoted steam reforming of methane at very low temperature like as 423K.

  • 固体酸化物の格子酸素と金属の協奏機能をもつ水素製造用触媒に関する研究

    科学研究費助成事業(早稲田大学)  科学研究費助成事業(特定領域研究)

    Project Year :

    2007
     
     
     

     View Summary

    炭化水素の水蒸気改質にはNi/Al203系触媒が用いられているが、この触媒の問題点は炭素析出による活性劣化である。本研究では,PtおよびPdといった貴金属を活性成分として用い、活性と安定性の向上を目的として触媒の担体にペロブスカイト型酸化物を適用して触媒特性を検討した。また、過渡応答法を用いて反応機構について、格子酸素の役割について検討を行った。担体にはLaAl03, La0.8Sr0.2Al02.9を用いた。比較用に&#61537;-Al203,を用いた。活性金属のPd, Ptは含浸法にて1wt%になるよう担持した。活性試験は固定床常圧流通式反応器で、1073Kにて反応を行った。過渡応答測定では供給ガスの切り替え直後の生成ガス濃度の推移を追跡、解析した。
    Pd/α-Al203、Pt/α-Al203両触媒を用いて固定流通式反応器によって定常条件下での反応を行ったところ、Pd触媒、Pt触媒ともにα-Al203では劣化が起きた。これは炭素析出または活性成分である貴金属のシンタリングによる活性劣化と考えられる。一方LaAl03を担体とした場合には、α-Al203担体を用いた場合と比較して、著しく活性と安定性が向上した。特に、Ptはα-Al203担体ではほとんど活性を示さないのに対して、LaAl03を担体とするとPdよりも高い活性を示した。
    種々の過渡応答測定の結果により、Pt/LaAl03ではLangmuir-Hinshelwood機構に加え、酸素が格子酸素として担体中に取りこまれてから消費されるMars-van Krevelen機構も同時に起こっていることが示唆された。L-H機構とMVR機構のCO, CO2生成に対する寄与の割合は、L-H機構約40%、MVR機構約60%となり、担体中の格子酸素の反応への寄与が大きいことがわかった。

  • Asymmetric oxygen-permeable membrane synthesis and its utilization for methane oxidation

    Project Year :

    2002
    -
    2005
     

     View Summary

    A disk-type Sm_<0.4>Ba_<0.6>Co_<0.2>Fe_<0.8>O_<3-δ> perovskite-type mixed-conducting membrane was applied to a membrane reactor for the partial oxidation of methane to syngas (CO + H_2). The reaction was carried out using Rh (1 wt%)/MgO catalyst by feeding CH_4 diluted with Ar.
    While CH_4 conversion increased and CO selectivity slightly decreased with increasing temperature, a high level of CH_4 conversion (90%) and a high selectivity to CO (98%) were observed at 1173 K. The oxygen flux was increased under the conditions for the catalytic partial oxidation of CH_4 compared with that measured when Ar was fed to the permeation side. We investigated the reaction pathways in the membrane reactor using different membrane reactor configurations and different kinds of gas. In the membrane reactor without the catalyst, the oxygen flux was not improved even when CH_4 was fed to the permeation side, whereas the oxygen flux was enhanced when CO or H_2 was fed. It is implied that the oxidation of CO and H_2 with the surface oxygen on the permeation side improves the oxygen flux through the membrane, and that CO_2 and H_2O react with CH_4 by reforming reactions to form syngas.

  • 低エネルギー放電を用いた天然ガスからの水素エネルギーと高機能炭素の併産プロセス

    日本学術振興会  科学研究費助成事業 若手研究(A)

    Project Year :

    2002
    -
    2003
     

    関根 泰

     View Summary

    本研究により、LEP放電はメタンの二酸化炭素リフォーミング、炭化水素/アルコールのスチームリフォーミング、重合、部分酸化といった多種多様な反応をサポートしうる。また、LEP放電と触媒を組み合わせることにより、常温でも電子照射によって触媒が活性化を受け、高い触媒能を発現することがわかった。
    メタンリフォーミング反応に低温、常圧、無触媒条件下において、LEP放電を適用したところ、リフォーミング反応が優勢に進行し、目的生成物が選択的に得られた。その際に炭素析出やワックスの生成などがほとんどないために、長時間安定した運転が可能であった。
    投入電力、ギャップ長、供給ガス流量等のパラメーターをコントロールすることで、選択率を変化させることなく、転化率のみを変えることができ、それに伴い目的生成物である水素の生成量も容易に、素早くコントロールすることができた。そのため、本LEP放電法は、従来の触媒反応では難しい、素早い負荷応答性があり、反応温度が低温であることから、始動も非常に速いと言える。
    上記のようなメリットの他にも、リフォーミング自体を無触媒で行えるため、失活や炭素析出の問題がなく、原料のS/C比も任意の比率で反応が行えるなど、LEP放電法によるスチームリフォーミング反応は触媒系に比べて種々のメリットがあることが分かった。
    エネルギー効率については、放電場での消費電力を用いて計算すると、メタンのスチームリフォーミング反応において、最高で78%と高く、電源及びパルス波形の最適化によりさらなる効率の向上が見込める事が分かった。水素製造における既存の放電プロセスではその効率は95MJ/kgH2程度が下限であったが、本プロセスにおいてはこれらを大きく下回り、物質合成やエネルギー製造といった多種多様な応用が可能である。

  • Clean Coal Production by Column Floatation Process

    Project Year :

    1999
    -
    2002
     

     View Summary

    Column flotation is one of the promising processes for the low-cost next generation coal cleaning technologies. As for the column flotation system, many efforts have focused on optimization of apparatus and/or improvement of flotation results so far. However there have been few studies that tried to estimate the relation of flotation results and characteristics properties of coal. We employed a continuous column flotation system for the simple coal cleaning process. Samples used in this study were Adaro, Wallarah, Ermelo, Datong, Taiheiyo, and they were crushed and sieved under 150μm. Then we investigated the demineralization in the column flotation system to estimate the flotation behavior by measuring the contents of inorganic elements in the cleaned coal and the tail refuse. Furthermore we investigated the change in the distribution of coal minerals and their average particle size during the flotation. Each steady state was 5〜14 min after starting the experiment.
    As a result, Wallarah was suitable for continuous column flotation. On the other hand, the flotation result of each brown coal (Pasir, Adaro, Berau) was different tendency. We found that column floatation process was a good way to recover carbonaceous materials from low rank coal. This process is very simple so it is suitable for application in Asian countries.

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Presentations

  • 表面プロトニクスが生み出す低温触媒反応

    関根 泰  [Invited]

    日本化学会のシンポジウム 

    Presentation date: 2020.03

  • グリーン水素製造・貯蔵輸送・利用の現状と今後

    関根 泰  [Invited]

    日本化学会アドバンステクノロジーセッション 

    Presentation date: 2020.03

  • 2050年を見据えたCO2回収・利用技術と計算科学への期待

    関根 泰  [Invited]

    ポスト京シンポジウム  (東京国際フォーラム) 

    Presentation date: 2020.03

  • 水素・炭化水素・二酸化炭素に関連した固体触媒プロセスと膜応用の可能性

    関根 泰  [Invited]

    未来を拓く無機膜環境・エネルギー技術シンポジウム  (東大) 

    Presentation date: 2019.11

  • Surface ionics/protonics for catalysis at low temperatures

    Yasushi SEKINE  [Invited]

    International Symposium on C1 Gas Refinery  (韓国) 

    Presentation date: 2019.10

  • 水素社会実現に向けた課題と今後の我が国のエネルギー技術

    関根 泰  [Invited]

    (枚方) 

    Presentation date: 2019.10

  • 二酸化炭素回収・利用技術の現状と今後

    関根 泰  [Invited]

    ポスト京シンポジウム  (八重洲カンファレンスセンター) 

    Presentation date: 2019.09

  • Catalytic reaction at low temperature by surface protonics

    Yasushi. Sekine  [Invited]

    シンポジウム  (スイスETH) 

    Presentation date: 2019.09

  • Low Temperature Catalytic Reaction in an Electric Field

    Yasushi SEKINE

    日韓触媒シンポジウム  (韓国) 

    Presentation date: 2019.05

  • 表面プロトニクス・イオニクスと低温作動触媒

    関根 泰

    先進研究講演会  (早大) 

    Presentation date: 2019.05

  • 低温での表面プロト二クスを活かしたアンモニア合成

    関根 泰

    日本化学会R&D懇話会  (東京) 

    Presentation date: 2019.05

  • 炭素-水素-酸素-窒素の元素循環とサステイナブルな利用

    関根 泰

    公開シンポジウム「サステイナブルな社会に向けた科学技術と自然界での炭素・水素・酸素・窒素の循環の調和」  (日本学術会議) 

    Presentation date: 2019.04

  • Investigation of heterogenous catalysis using surface ion hopping and its utilization

    Yasushi SEKINE

    日本化学会 受賞記念講演  (兵庫) 

    Presentation date: 2019.03

  • イノベーション技術としての電場触媒反応

    関根 泰

    講演会  (長崎) 

    Presentation date: 2019.01

  • 表面プロト二クスによる低温での反応と表面伝導メカニズムの解析

    関根 泰

    表面技術協会関東支部講演会  (長野) 

    Presentation date: 2018.12

  • 表面プロト二クスを活かした低温アンモニア合成

    関根 泰

    JACI講演会  (東京) 

    Presentation date: 2018.12

  • 表面プロトニクス・イオニクスを活かした非在来型触媒反応

    関根 泰

    触媒学会つくば地区講演会  (つくば) 

    Presentation date: 2018.11

  • 電解合成への期待:次世代の化学プロセスに向けて

    関根 泰

    電解技術討論会  (横浜国大) 

    Presentation date: 2018.11

  • Catalytic steam reforming of biomass-derivatives for hydrogen production

    Yasushi SEKINE  [Invited]

    シンポジウム  (サウジアラビア) 

    Presentation date: 2018.11

  • Low temperature catalysis by surface protonics

    Yasushi SEKINE

    シンポジウム  (韓国DGIST) 

    Presentation date: 2018.11

  • Surface Protonics Promotes Heterogeneous Catalysis

    Yasushi SEKINE

    シンポジウム  (オーストラリア) 

    Presentation date: 2018.11

  • 天然ガス転換、水素製造と二酸化炭素利用技術に関する現状と今後の展望

    関根 泰

    講演会  (横浜) 

    Presentation date: 2018.10

  • 表面プロトニクスを活かした低温作動触媒

    関根 泰

    カンファレンス  (慶應義塾) 

    Presentation date: 2018.10

  • Mechanistic study of oxidative coupling of methane over Ce-W-O system catalysts in the electric field at low temperature

    S. Ogo, A. Sato, K. Murakami, H. Nakatsubo, K. Iwasaki, K. Sugiura, T. Higo, T. Yabe, A. Ishikawa, H. Nakai, Y. Sekine

    2018 International Symposium on Advancement and Prospect of Catalysis Science & Technology  (オーストラリア) 

    Presentation date: 2018.07

  • Low temperature catalytic reaction in an electric field

    Y. Sekine

    2018 International Symposium on Advancement and Prospect of Catalysis Science & Technology  (オーストラリア) 

    Presentation date: 2018.07

  • 電場触媒反応を利用した温和な条件下でのアンモニア合成技術

    関根 泰  [Invited]

    日本化学会の春季年会  (東京) 

    Presentation date: 2018.03

  • 電場触媒反応による低温メタン酸化カップリング

    小河 脩平, 佐藤綾香, 関根 泰

    高難度選択酸化反応研究会シンポジウム  (東京) 

    Presentation date: 2018.01

  • [特別講演]メタン転換のための触媒反応のこれまでと今後

    関根 泰

    革新的触媒シンポジウムにて下記2件の依頼講演を行いました。  (神奈川) 

    Presentation date: 2017.11

  • アンモニア合成の新手法

    関根 泰

    講演会にて下記1件の依頼講演を行いました。  (東京) 

    Presentation date: 2017.10

  • 非在来型触媒反応による天然ガス転換と水素製造

    関根 泰  [Invited]

    触媒学会 第二回キャタリシスセミナー  (新潟) 

    Presentation date: 2017.09

  • CO2化学的転換利用の現状と今後

    関根 泰  [Invited]

    石油学会 新エネルギー部会講演会  (東京) 

    Presentation date: 2017.09

  • 天然ガスからの水素・化学品製造のための低温触媒反応プロセス

    小河脩平, 渡部 綾, 関根 泰

    触媒学会 第120回触媒討論会  (愛媛) 

    Presentation date: 2017.09

  • 水素のこれまでとこれから

    関根 泰

    講演会  (横浜市) 

    Presentation date: 2017.06

  • 水素をつくる これまでとこれから

    関根 泰

    講演会  (東京) 

    Presentation date: 2017.05

  • 水素をつくる これまでとこれから

    関根 泰

    触媒学会水素シンポジウム  (東京本郷) 

    Presentation date: 2016.11

  • 水素社会の現状と展望、水素製造と貯蔵・運搬について

    関根 泰  [Invited]

    (横浜市講演会) 

    Presentation date: 2016.09

  • 水素社会の現状と展望、水素製造と貯蔵・運搬について

    関根 泰

    講演会  (都内(機械振興会館) 

    Presentation date: 2016.06

  • Low temperature hydrogen production by ethanol steam reforming over Pt-supported catalysts assisted by electric field

    Shuhei Ogo, Saori Sakurai, Naoya Tsunashima, Ryo Manabe, Yasushi Sekine

    3rd JPI-KSIEC Joint Symposium  (韓国麗水(Yeosu)) 

    Presentation date: 2016.05

  • 水素社会の現状と展望、水素製造と貯蔵・運搬について

    関根 泰

    日本技術士会講演会  (都内(機械振興会館)) 

    Presentation date: 2016.01

  • 超空間制御と電場中での触媒反応を活かしたメタン転換

    関根 泰

    「触媒学会横浜地区講演会:超空間制御触媒の創製と物質変換の新機軸」  (横浜国立大) 

    Presentation date: 2015.11

  • 水素のこれまでとこれから

    関根 泰

    石油学会の講演会  (名古屋) 

    Presentation date: 2015.11

  • 水素製造ならびに水素キャリアのためのプロセスと触媒・材料

    関根 泰

    日本学術振興会講演会  (東京) 

    Presentation date: 2015.10

  • 水素製造と利用の技術の現状と今後

    関根 泰  [Invited]

    化学工学会  (札幌) 

    Presentation date: 2015.09

  • 非在来型触媒プロセスによるメタン転換と水素製造

    関根 泰

    触媒学会若手会夏の研修会  (群馬) 

    Presentation date: 2015.08

  • シェールガス時代のエネルギーと水素製造

    関根 泰

    「未来社会創製の会」  (早大) 

    Presentation date: 2015.06

  • エネルギーと環境のいまと今後

    関根 泰

    「先進研究講演会」  (早大) 

    Presentation date: 2015.05

  • シェールガス革命とメタンのこれから

    関根 泰  [Invited]

    触媒学会東日本支部・東北地区講演会「Theメタン~古くて新しいエネルギー~」  (宮城仙台) 

    Presentation date: 2015.03

  • 環境エネルギー分野の現状俯瞰ならびに同分野におけるプラズマ場・電場利用の化学

    関根 泰  [Invited]

    学振委員会  (東工大) 

    Presentation date: 2015.03

  • 資源エネルギーと触媒技術の展望

    関根 泰

    第50回触媒フォーラム(50th記念)「これからの社会に求められる触媒技術、現状と今後の展望  (神奈川) 

    Presentation date: 2015.01

  • 水素製造と水素キャリアの現状とこれから

    関根 泰

    石油学会・触媒シンポジウム  (東京) 

    Presentation date: 2014.11

  • 2.シェールガス・天然ガス・石油を起源とした化学の今後

    関根 泰

    (東工大) 

    Presentation date: 2014.10

  • 担持金属触媒のXAFSによる微細構造解析と触媒開発

    関根 泰

    第二回SPring-8グリーンサステイナブルケミストリー研究会  (東京) 

    Presentation date: 2014.07

  • プラズマ・電場を利用した化学反応の学理と応用

    関根 泰

    日本電磁波エネルギー応用学会の講演会  (東工大) 

    Presentation date: 2014.05

  • プラズマ・電場中での触媒反応の学理と応用

    関根 泰

    電気学会全国大会シンポジウム  (松山) 

    Presentation date: 2014.03

  • シェールガスをはじめとする非在来型化石資源と今後のエネルギー・化学

    関根 泰

    日本化学連合シンポジウム  (東京) 

    Presentation date: 2014.03

  • 電場印加による低温での触媒反応

    関根 泰

    北関東地区懇話会・シンポジウム「最近の触媒反応プロセスの進展」  (宇都宮) 

    Presentation date: 2014.02

  • HYDROGEN PRODUCTION BY STEAM REFORMING OF TOLUENE OVER Ni/PEROVSKITE OXIDE CATALYST

    Yasushi SEKINE

    International Conference on Hydrogen Production (ICH2P-2014)  (九州) 

    Presentation date: 2014.02

  • 若手研究者のキャリアパスについて

    関根 泰

    講演会  (学内) 

    Presentation date: 2014.01

  • シェールガスを生かした天然ガス化学・石油化学の今後

    関根 泰

    第32回石油学会中国・四国支部講演会  (山口・岩国(JX麻里布)) 

    Presentation date: 2013.11

  • 「シェールガスと今後の化学技術・産業」

    関根 泰

    CSJ化学フェスタ  (東京船堀タワーホール) 

    Presentation date: 2013.10

  • 天然ガスの転換・利用と水素製造・利用のための非在来型触媒技術

    関根 泰

    化学工学会触媒分子反応工学分科会講演会  (三菱レーヨン広島大竹) 

    Presentation date: 2013.10

  • 非在来型触媒反応を生かした水素製造・天然ガス転換の学理と応用

    関根 泰

    (九州) 

    Presentation date: 2013.09

  • ペロブスカイト型等の複合酸化物を担体として用いた触媒反応の学理と応用

    関根 泰

    触媒サマーセミナー  (箱根) 

    Presentation date: 2013.07

  • 天然ガス転換および水素製造に関連した非在来型触媒プロセス

    関根 泰

    工業触媒研究会  (神奈川) 

    Presentation date: 2013.05

  • 非在来型水素/合成ガス関連反応の現状と今後

    関根 泰

    (つくば) 

    Presentation date: 2013.01

  • 天然ガスの転換反応における在来型・非在来型手法の現状と今後の展望

    関根 泰

    (東京) 

    Presentation date: 2013.01

  • 非在来型触媒反応と水素製造

    関根 泰

    新化学技術推進協会(JACI)講演会  (東京) 

    Presentation date: 2012.12

  • Low temperature hydrogen production by steam reforming of methane

    Kazumasa Oshima, Tatsuya Shinagawa, Yasushi Sekine  [Invited]

    17th Malaysian Chemical Congress及びカンボジア  (マレーシア) 

    Presentation date: 2012.10

  • エネルギー分野における触媒の今後

    関根 泰

    北九州学術研究都市産学連携フェア  (北九州) 

    Presentation date: 2012.10

  • 依頼講演 1F09 水素の製造と利用に関連した最近の国内外の研究動向

    関根 泰  [Invited]

    第110回触媒学会討論会  (福岡) 

    Presentation date: 2012.09

  • エネルギー・環境分野における最近の話題

    関根 泰

    (神奈川) 

    Presentation date: 2012.08

  • 研究を進める上での資金獲得とキャリア形成‐スパイラルアップの方法論‐

    関根 泰

    「研究戦略セミナー」  (学内) 

    Presentation date: 2012.07

  • 非在来型触媒反応の学理と応用

    関根 泰

    公開講演会「先進研究講演会」  (大学内) 

    Presentation date: 2012.05

  • 一つの基準で俯瞰した我が国のエネルギーと そこからあぶり出される課題

    関根 泰

    講演会  (都内) 

    Presentation date: 2012.04

  • Hydrogen production by steam reforming of hydrocarbon over Ni/perovskite catalyst

    Y. Sekine

    International Conference on Global Sustainability  (マレーシア) 

    Presentation date: 2012.04

  • 水素製造・利用に関連する触媒技術の動向

    関根 泰

    第9回工業触媒研究会フォーラム  (東京・化学会館) 

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Specific Research

  • 再エネ電力を用いたオンデマンドで低温作動する固体触媒プロセスの創製

    2021  

     View Summary

    化石資源消費削減の視点から、メタンドライリフォーミング(DRM)や水素を還元剤とする逆水性シフト(RWGS)、CO2メタネーションを検討した。触媒層に直流電流を印加することで触媒性能を向上させる電場触媒反応によって500 K程度の低温度でもDRMやRWGS、CO2メタネーションが進行することを発見した。1 wt% Pt担持CeO2のDRM活性を評価するために活性評価試験を行った。従来の反応が進行しない700 K以下の低温度領域においてCH4, CO2共に高い転化率が確認された。それぞれの見かけ活性化エネルギーについて、電場なしでは104 kJ mol-1、ありでは4.82 kJ mol-1と大きく低下した。電場を印加することでCO2の吸着種であるcarbonateが増加することが確認された。また、反応中においてこれらのcarbonate種が消費され、COとして解離することが分かった。

  • バイオマスエタノールの直接水蒸気改質による水素製造のための高性能触媒の開発

    2013  

     View Summary

    我々はこれまで、バイオマスエタノールの水蒸気改質用触媒として高活性であるCo触媒において、微量の鉄を表面に修飾することによるacetate種吸着の安定化が、副生成物の抑制や活性に効果的であることを見出した。今年度さらに、アルカリ金属を加えることで副生成物の抑制が可能であることを見出した。具体的には、Co/K/α-Al2O3が優れた性能を示すことを見出し、K添加量の変化によって活性にどのような影響を及ぼすかを検討するため、Kを0.3~3.0 wt%となるように担持したCo/K/α-Al2O3の活性試験を比較した。K添加量を増加させると転化率、水素収率が1.0~2.0 wt%程度で最大となった。またK添加量の増加に伴って析出炭素量が低下した。これは、エタノールまたは中間体の吸着状態がK添加によって変化したためではないかと考え、IR測定を行い、各温度での表面吸着種について検討した。その結果、323 Kでエタノールを吸着させるとethoxide種として吸着し、温度を上げるとacetate種に変化することがわかった。温度を上げていくと、Co/α-Al2O3では723 Kでピークが消失しているのに対してCo/K/α-Al2O3では高温でもピークが残存する結果となった。K添加によってacetate種の吸着種が水の存在下でも安定化されることがわかった。Kを添加したCo/K/α-Al2O3では、Co/α-Al2O3と比較してacetate種が高温でも残存し、安定化されたことにより分解によるCH4の生成が抑制された。水の存在下でもCo/K/α-Al2O3ではacetate種が高温において安定化され、水蒸気雰囲気においてもacetate種の安定性が高い活性に寄与していた。これらから、安価なKを微量、コバルト触媒に添加することによって高性能なバイオマスエタノールからの水素製造触媒とすることが出来ることを見出した。

  • 安価な鉄酸化物を用いた低温作動高活性水性ガスシフト触媒の創出と機能解明

    2012  

     View Summary

    水性ガスシフト反応はH2の精製や合成ガスのH2/CO比の調整に用いられる反応であり、COとH2Oを反応させ、H2とCO2を生成する反応である。我々は、これまでの予備的な検討において、1.1 wt%Pdを鉄酸化物に担持した触媒について、Pd、Kの両者が担持されていると高活性という特異的な結果を見出した。今回、本特定課題においては、鉄系酸化物をベースとした触媒、さらにCo3O4を担体とした触媒についても詳細に検討した。Pdの担持量を振った際に、Pdの担持量が少量である触媒ではKが担持されていなくてもメタネーションは著しいがある程度活性が高いという結果が得られた。これらより、Pd、Kが別々に担体に作用している可能性を示唆した。Pdは担体の還元を促進する因子、Kは担体の還元を抑制する因子であると推測する。また、Pdの担持量を少量にしても活性があることから、今まで研究されてきたFe系触媒とは反応機構や活性点が異なり、Pdは単に担体の還元促進にしか寄与していない可能性が示唆された。また、Fe系触媒と異なり、メタネーションや炭素析出が生じたことからコバルトを使うことによる弊害も生じた。また、活性点についてであるが、Pdは単に補佐であり、Co自体が活性点である可能性が高いと考える。この視点から、TPR、XRD、XAFSでの結果を踏まえ、CoOとCo metalの間が活性点である可能性が高く、またPdとCoは合金化は合金化している可能性は高いが、高活性の原因ではないと示唆された。今後、メタネーションや炭素析出の現象の原因を今後検討していく必要があり、またPdの担持量が少量でも高活性であることからPd以外の担持金属についても検討していく必要がある。 また、Pd/K/Fe2O3の高活性の原因追究として、Cs担持触媒、Na担持触媒についてXAFS、STEMを用いて詳細に検討したところ、Cs担持触媒ではCs/Pdのmol比によりPdの微細構造が異なっている可能性が示唆され、Pdの粒子径の影響が強いと考えられ、この結果を類推適用した結果、alkali/Pdのmol比=2で最も高活性の高いPd/K/Fe2O3についても粒子径が最も小さいと考えられる。

  • 水素製造のための非LH型で作動する低温水性ガスシフト用触媒の開発

    2008  

     View Summary

    水性ガスシフト反応は合成ガスのH2/CO比調整を行う重要な反応である.現在の水性ガスシフト反応用触媒は,一般的に高価であるため, より安価な触媒の開発が求められている.そこで我々はFeに着目した.安価なFeを用いて反応温度を低温化することができれば, 低コストでH2/CO比の調整を行うことができる.本研究ではFe2O3をベースとした新規触媒開発を目的とした.担体は市販のFe2O3(以降Fe2O3-1), もしくは沈殿法により調製したFe2O3を用いた.また,沈殿法においては前駆体にFe(NO3)3・9H2O,沈殿剤にそれぞれK2CO3,NH3aqを用いてFe2O3を調製した(それぞれFe2O3-2,Fe2O3-3).また,Fe2O3へのPd,Kの担持は含浸法を用いた.活性試験は固定床常圧流通式反応器を用いて行った.反応器は外径8 mm,内径6 mmの石英管を用いた.触媒重量は80 mg,反応ガスの組成は体積比でH2O/CO/H2/N2/Ar = 30/6/42/13/9 とし,W/F = 2.99 g-cat h mol-1(触媒重量80 mg)とした.反応温度は573 K,523 K,473 Kで,反応時間はいずれも185 min行った.反応直後の出口ガスをGC-FIDを用いて分析した.沈殿法で調製したFe2O3-2とFe2O3-3にPdを担持したPd/Fe2O3-2とPd/Fe2O3-3について,反応温度573 Kにて活性試験を行った.その結果,Pd/Fe2O3-3は活性がほとんど発現しなかったが,Pd/Fe2O3-2は工業用触媒よりも高い活性を示すことが確認された.この結果より,Pd/Fe2O3が高活性を示す要因として沈殿剤であるK2CO3中のKが関係していると考え,Kを含まないFe2O3-1にKを担持した触媒、KとPdを担持した触媒について活性試験を行った.その結果,K/Fe2O3-1は活性を示さなかったが,Pd/K/Fe2O3-1はPd/Fe2O3-2と同様に高い活性を示した.Fe2O3以外の担体においても高活性を示すかどうかを検討するために,Fe2O3と同様に酸化還元特性を持つCeO2と酸化還元特性を持たないSiO2にKとPdを担持したPd/K/CeO2とPd/K/SiO2について573 Kにて活性試験を行った.その結果,Pd/K/CeO2では活性が発現したが,Pd/K/SiO2は活性が発現しなかった.この結果より,酸化還元特性を有する担体,Pd,Kの三者のシナジー効果によって活性が発現する可能性が示された.PdとKの担持量が活性にどのような影響を与えるかを検討するために,様々な担持量で担持したPd/K/Fe2O3-1について活性試験を行った.K/Pd mol比が約2のところで特に高い活性を示すことがわかった.このことからKとPdの特定の構造が担体との相互作用により高い水性ガスシフト活性を示すと考えられる.

  • 電場により表面電荷を制御した担持金属とペロブスカイト酸化物格子酸素との協奏と反応

    2007  

     View Summary

    電場印加反応場中での触媒反応としてC-C結合、C-H結合、C-O結合、O-H結合を有するエタノールの分解を検討した。静電場を印加しない触媒反応(Mode A)と、反応場に静電場を印加した触媒反応(Mode B)の2種を比較し、静電場が触媒反応におよぼす影響ついて比較した。反応メカニズムに関する知見を得るために様々な実験を行った結果、放電と触媒のハイブリッド反応ではまず原料分子は放電場により活性ラジカル種に分解され、その後ラジカルルが触媒と反応することによりシナジー効果が発現しているという可能性を見出した。触媒として5 wt %Pt/CeO2を用い、電流値3.0 mAで温度を423~673 Kと変化させて反応を行った。静電場印加反応場中での触媒反応(Mode B)では静電場を印加しない触媒反応(Mode A)に比べ全ての温度域で転化率が向上し、高温になるほど活性向上の度合いが大きくなっていることが確認された。選択率に関してはMode B はMode Aとはわずかに異なるがほぼ似た傾向を示している。ここで触媒層に電流が流れることによる加熱の影響を検討するため、サーモグラフィーにより反応場の温度測定を試みた。石英管が赤外線を透過しないので反応場の温度を直接測定することが困難であるため、石英管表面の温度と触媒層温度との相関を求め、静電場の影響を検討したところ、反応場の温度上昇は5~10 K程度であった。これよりMode Bでは触媒に電流を流すことにより、加熱の影響だけでなく静電場と反応場の相互作用により活性が向上したと考えられる。

  • 液体燃料の低エネルギー放電による常温液相改質

    2001  

     View Summary

    本年度、特定課題研究によって、私は常温常圧での低エネルギー放電による炭化水素の改質について検討した。低エネルギー放電としては、直流の微少パルスアーク放電を用い、全体として投入電力を10W程度に抑えた。これにより、メタン、LPG、ガソリンあるいは各種アルコールといった燃料が常温あるいは気化温度(百数十度程度)において効率よく二酸化炭素あるいは水蒸気と反応して、合成ガスあるいは水素へと変換された。この低エネルギーDCパルス放電は、非平衡放電であり、高い電子温度を有しながら、ガス温度は常温のままを維持することができ、これによって、これまで不可能であった低い温度領域での炭化水素の改質が可能となった。本放電は、80%近い高いエネルギー効率を有しながら、電源のオンオフにより瞬時に応答し、印加するパルス数に応じて転化率・水素生成量をコントロール可能であり、また炭素の析出もないため、民生用の水素生成装置としての応用が可能である。今後の課題として考えられる点は、効率の更なる向上を実現させるための高効率電源開発および、集積化による大型化、それにともなう電磁ノイズの遮蔽である。これらをクリアすることができれば、自動車用あるいは家庭用の燃料電池への水素供給改質への応用の道が開かれるものと考えている。

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Syllabus

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Committee Memberships

  • 2021.02
    -
    Now

    METI  Green Inovation Project

  • 2020.07
    -
    Now

    Japan  Green Inovation Strategy

  • 2018
    -
    Now

    JST  さきがけ総括

  • 2017.02
    -
    Now

    Elsevier  FUEL誌プリンシパルエディター

  • 2016.06
    -
    Now

    Natural Gas Conversion Board  Board Member

  • 2018
    -
    Now

    NEDO  未踏チャレンジ2050総括

  • 2017.11
    -
    Now

    日本学術会議  特任連携会員

  • 2019
    -
    2020.01

    文部科学省・経済産業省  革新的環境イノベーション委員

  • 2018
    -
    2019

    文部科学省・経済産業省  ポテンシャル検討会委員

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    文部科学省  環境エネルギー科学技術委員会

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