研究者詳細 - 薩摩　篤

論文 - 薩摩　篤

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Gas-phase synthesis of morphology-controlled Pt nanoparticles and their impact on cinnamaldehyde hydrogenation

Kato Sosuke, Ohyama Junya, Machida Masato, Satsuma Atsushi

CATALYSIS SCIENCE & TECHNOLOGY 9 巻 ( 9 ) 頁： 2097-2102 - 2102 2019年5月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Catalysis Science and Technology

Gas-phase synthesis of morphology-controlled Pt nanoparticles (PtNPs) is conducted with carbon monoxide as a protective agent. Depending on the preparation temperature, Pt nanocubes with Pt{100} or cuboctahedra with Pt{111} and Pt{100} facets are formed by reducing Pt/C and Pt/SiO2 under a CO/H2 flow, although Pt nanospheres are formed under a H2 flow in the absence of CO. The influence of the Pt nanoparticle morphology on cinnamaldehyde hydrogenation is explored by comparing the hydrogenation performances of Pt nanocubes, cuboctahedrons, and spheres with various particle sizes. The hydrogenation activity and selectivity toward cinnamyl alcohol are enhanced in the order Pt nanocuboctahedra > Pt nanocubes > Pt nanospheres; thus, Pt{111} facets > Pt{100} facets > rounded (stepped) surface with respect to the surface structure.

DOI： 10.1039/c9cy00158a

Tandem Base-Metal Oxide Catalyst: Superior NO Reduction Performance to the Rh Catalyst in NO-C3H6-CO-O-2

Ueda Kakuya, Tsuji Masashi, Ohyama Junya, Satsuma Atsushi

ACS CATALYSIS 9 巻 ( 4 ) 頁： 2866-2869 - 2869 2019年4月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：ACS Catalysis

We developed a high-performance PGM-free three-way catalyst based on a new strategy: a combination of two base-metal oxide catalysts with tandem configuration for hydrocarbon preferential oxidation (PROX) in upstream of exhausted gas and efficient purification of NO by CO in the downstream flow. The effectiveness of the tandem concept is verified by a combination of ZnCr2O4 for C3H6-PROX and CuCo2O4 for NO-CO-O2 reaction. The combination achieved a comparable performance to a Rh/ZrO2 catalyst, in terms of NO conversion (66.9%) and a superior performance regarding N2 yield (59.9%) and N2 selectivity (89.8%) at 300 °C.

DOI： 10.1021/acscatal.9b00526

Surface modification of Pt nanoparticles with other metals boosting the alkaline hydrogen oxidation reaction

Okubo Keiichi, Ohyama Junya, Satsuma Atsushi

CHEMICAL COMMUNICATIONS 55 巻 ( 21 ) 頁： 3101-3104 - 3104 2019年3月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Chemical Communications

To enhance the hydrogen oxidation reaction (HOR) activity of Pt/C under alkaline conditions, the catalyst's surface was modified with fifteen metals. The surface modification enhanced the activity of Pt/C for the HOR beyond a change in hydrogen binding energy (HBE), and this can be attributed to a change in the reactivity of surface oxygen species to adsorbed hydrogen species.

DOI： 10.1039/c9cc00582j

Enhanced alkaline hydrogen oxidation reaction by modifying Pt nanoparticle surface with another metal

Ohyama J., Okubo K., Satsuma A.

ECS Transactions 92 巻 ( 8 ) 頁： 733 - 738 2019年

記述言語：日本語掲載種別：研究論文（学術雑誌）出版者・発行元：ECS Transactions

The cell performance of anion exchange membrane fuel cells (AEMFCs) has been getting closer to that of proton exchange membrane fuel cells (PEMFCs) by improvement of hydrogen oxidation reaction (HOR) catalysts on anodes with the help of the state-of-the-art AEMs having high ion conductivity. However, development of the alkaline HOR catalysts is still demanded to reduce the usage of precious metals on AEMFC anode. Here, Pt/C catalyst is modified to improve the HOR activity using fifteen metals on the group 4-11 of the 4th and 5th period in the periodic table except for Tc, i.e., Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zr, Nb, Mo, Ru, Rh, Pd, Ag. In addition, the hydrogen binding energy of modified Pt/C and the oxophilicity of modifying metals are evaluated to reveal the mechanism of improved/lowered HOR activity.

DOI： 10.1149/09208.0733ecst

In situ and operando analysis of environmental catalysts - Studies on reaction mechanism and active site

Murata K., Ueda K., Mahara Y., Ohyama J., Satsuma A.

Catalysis 31 巻頁： 242 - 266 2019年

記述言語：日本語掲載種別：研究論文（学術雑誌）出版者・発行元：Catalysis

In situ and operando analyses are the methods to observe the real features of catalysts under the reaction conditions. These methods can clarify the dynamics of active species of catalysts and reaction scheme on catalyst surface through transient response method, kinetic study, temperature dependence of catalysts and products, and so on. In this review, progress in in situ and operando analyses is summarized with emphasis on environmental catalysts, i.e., catalysts for combustion, selective reduction of NO, automotive three-way catalysis, and related materials.

DOI： 10.1039/9781788016971-00242

Structure–Activity Relationship of Iron Oxides for NO Reduction in the Presence of C<inf>3</inf>H<inf>6</inf>, CO, and O<inf>2</inf> 査読有り

Ueda K., Ohyama J., Sawabe K., Satsuma A.

Chemistry - A European Journal 25 巻 ( 61 ) 頁： 13964 - 13971 2019年

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Chemistry - A European Journal

Spinel-type NiFe2O4 exhibited the highest NO reduction activity among base-metal oxides under simulated exhaust of a gasoline-powered vehicle. The structure–activity relationship of iron oxides has been investigated through both experimental and computational studies. Spinel iron oxide (γ-Fe2O3) exhibited a much higher NO reduction activity than that of iron oxide with other structures (α-Fe2O3 and LaFeO3). Operando IR measurements clarified that the spinel structure facilitated the reaction between NOx and adsorbed oxidized hydrocarbon or cyanide species. The high reactivity of the spinel structure was ascribed to the high adsorption energy of NO, as elucidated by DFT calculations. Furthermore, molecular orbital calculations demonstrated that the local coordination structure of the spinel iron oxide induced the involvement of not only σ but also π orbitals during NO adsorption on Fe atoms. This work clarified the origin of the structure-dependent activity of metal oxides, with a focus on their local coordination structures.

DOI： 10.1002/CHEM.201902994

Shape Control Preparation of Supported Platinum Nano-octahedra by Ethylene Treatment for Enhancement of Selective Hydrogenation of Cinnamaldehyde 査読有り

Ohyama J., Kato S., Machida M., Satsuma A.

Chemistry Letters 48 巻 ( 10 ) 頁： 1203 - 1205 2019年

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Chemistry Letters

The particle shape of a Pt/C catalyst is confined to octahedral by adding ethylene in an H2 stream during reduction of Pt/C. The Pt nano-octahedra enclosed by Pt{111} show higher catalytic activity for selective C=O hydrogenation of cinnamaldehyde in comparison with Pt nano-cuboctahedron, cube, and sphere.

DOI： 10.1246/CL.190462

Quantum Chemical Computation-Driven Development of Cu-Shell-Ru-Core Nanoparticle Catalyst for NO Reduction Reaction 査読有り

Ohyama J., Shibano J., Satsuma A., Fukuda R., Yamamoto Y., Arai S., Shishido T., Asakura H., Hosokawa S., Tanaka T.

Journal of Physical Chemistry C 123 巻 ( 33 ) 頁： 20251 - 20256 2019年

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Journal of Physical Chemistry C

A supported Cu-based catalyst is designed for nitrogen oxide (NO) reduction reaction based on the previous exploration of Cu-M alloy nanoparticles by quantum chemical computations, where Cu-shell-Ru-core with incoherent interphase interfaces have been suggested as a candidate structure improving NO reduction activity. Here, such Cu-Ru nanoparticles are actually prepared in Al2O3-supported form by using electrostatic adsorption method as an adequate preparation method of supported core-shell alloy nanoparticle catalysts. Improved NO reduction activity by Cu-shell-Ru-core nanoparticles is demonstrated by NO-CO reaction activity tests on their Cu0/Ru surface in comparison to monometal surface of Cu and Ru nanoparticles.

DOI： 10.1021/ACS.JPCC.9B03687

Identification of active sites in CO oxidation over a Pd/Al<inf>2</inf>O<inf>3</inf> catalyst 査読有り

Murata K., Eleeda E., Ohyama J., Yamamoto Y., Arai S., Satsuma A.

Physical Chemistry Chemical Physics 21 巻 ( 33 ) 頁： 18128 - 18137 2019年

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Physical Chemistry Chemical Physics

The active sites of Pd/Al2O3 catalysts for CO oxidations were identified by investigating the dependence of CO oxidation activities on the surface structure and morphology of Pd nanoparticles. The maximum catalytic activity was obtained for Pd particles approximately 2 nm in particle size. We performed structural analyses on the Pd surface through infrared (IR) spectroscopy of the adsorbed CO molecules. A positive correlation was obtained between catalytic activity and the fraction of linear CO adsorbed on Pd corner sites and Pd(111) facets, indicating that these sites are highly active for CO oxidation. X-ray absorption fine structure (XAFS) and spherical aberration-corrected scanning transmission electron microscopy (Cs-STEM) measurements demonstrated that Pd nanoparticles less than 2 nm in particle size with amorphous-like structures and Pd particles with large, well-ordered structures favor the formation of a high fraction of corner sites and Pd(111) facets, respectively.

DOI： 10.1039/C9CP03943K

Twinned/untwinned catalytic gold nanoparticles identified by applying a convolutional neural network to their Hough transformed Z-contrast images

Yamamoto Yuta, Hattori Mizuki, Ohyama Junya, Satsuma Atsushi, Tanaka Nobuo, Muto Shunsuke

MICROSCOPY 67 巻 ( 6 ) 頁： 321-330 - 330 2018年12月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Microscopy

In this article, we demonstrate that a convolutional neural network (CNN) can be effectively used to determine the presence of twins in the atomic resolution scanning transmission electron microscopy (STEM) images of catalytic Au nanoparticles. In particular, the CNN screening of Hough transformed images resulted in significantly higher accuracy rates as compared to those obtained by applying this technique to the raw STEM images. The proposed method can be utilized for evaluating the statistical twining fraction of Au nanoparticles that strongly affects their catalytic activity.

DOI： 10.1093/jmicro/dfy036

Synthesis of Supported Bimetal Catalysts using Galvanic Deposition Method

Mahara Y., Ohyama J., Sawabe K., Satsuma A.

Chemical Record 18 巻 ( 9 ) 頁： 1306 - 1313 2018年9月

記述言語：日本語掲載種別：研究論文（学術雑誌）出版者・発行元：Chemical Record

Supported bimetallic catalysts have been studied because of their enhanced catalytic properties due to metal-metal interactions compared with monometallic catalysts. We focused on galvanic deposition (GD) as a bimetallization method, which achieves well-defined metal-metal interfaces by exchanging heterogeneous metals with different ionisation tendencies. We have developed Ni@Ag/SiO2 catalysts for CO oxidation, Co@Ru/Al2O3 catalysts for automotive three-way reactions and Pd−Co/Al2O3 catalysts for methane combustion by using the GD method. In all cases, the catalysts prepared by the GD method showed higher catalytic activity than the corresponding monometallic and bimetallic catalysts prepared by the conventional co-impregnation method. The GD method provides contact between noble and base metals to improve the electronic state, surface structure and reducibility of noble metals.

DOI： 10.1002/tcr.201700084

Time Resolved in situ DXAFS Revealing Highly Active Species of PdO Nanoparticle Catalyst for CH<inf>4</inf> Oxidation

Mahara Y., Murata K., Ueda K., Ohyama J., Kato K., Satsuma A.

ChemCatChem 10 巻 ( 16 ) 頁： 3384 - 3387 2018年8月

記述言語：日本語掲載種別：研究論文（学術雑誌）出版者・発行元：ChemCatChem

The highly active species of Pd/Al2O3 catalysts for methane combustion was revealed by in situ time-resolved dispersive X-ray absorption fine structure (DXAFS) spectroscopy. By using CH4 as a reduction agent, PdO in Pd/Al2O3 is reduced in a 2-step model involving Pd0 nucleation and growth of Pd0 domain in a PdO particle. Kinetic analysis of the 2-step model reduction of PdO nanoparticles leads to a suggestion that partial formation of Pd0 in a PdO particle accelerates methane combustion.

DOI： 10.1002/cctc.201800573

Formation of Rhodium Metal Ensembles that Facilitate Nitric Oxide Reduction over Rhodium/Ceria in a Stoichiometric Nitric Oxide–Carbon Monoxide–Propene–Oxygen Reaction

Junya Ohyama, Takumi Nishiyama, Atsushi Satsuma

ChemCatChem 10 巻 ( 7 ) 頁： 1651 - 1656 2018年4月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Wiley Blackwell

A series of ceria-supported Rh nanoparticles (NPs) that have various particle sizes of 2–7 nm was prepared to investigate the size effect of Rh NPs on NO reduction in NO–CO–C3H6–O2 under stoichiometric conditions. The turnover frequency (TOF) for NO reduction on Rh NPs increased drastically according to their particle size. The strong size dependence of the TOF was attributed to the oxidation states of Rh NPs but not to particle geometries, which include fractions of surface local sites (e.g., corner, edge, plane) and the surface crystal structures (e.g., Rh(1 1 1), (1 0 0)). The variation of the TOF with the Rh metal fraction suggested that Rh metal ensembles are highly active species for NO reduction.

DOI： 10.1002/cctc.201701842

Enhanced three way catalytic activity of NiFe2O4 by physically mixed metal oxides

Shiori Nagai, Kakuya Ueda, Junya Ohyama, Atsushi Satsuma

Catalysis Today 303 巻頁： 40 - 45 2018年4月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Elsevier B.V.

The NOx reduction activity of NiFe2O4 in automotive three-way catalysis was enhanced by physical mixing with CeO2, MgO, ZrO2, and Al2O3, while the mixing with TiO2 and Nb2O5 did not promoted the catalytic activity. On both pure NiFe2O4 and the physically mixed catalysts, NO was mainly reduced by C3H6 under the NO-C3H6-CO-O2 reaction conditions, because the temperature dependence of NO conversion in NO-C3H6-CO-O2 reaction was the same as that in NO-C3H6-O2 reaction. The in-situ FT/IR measurement revealed that the NO reduction proceeded with (1) partial oxidation of C3H6 to surface carboxylates, i.e., acetate and formate as good reductants for NO, and (2) reduction of NO by surface carboxylates. The metal oxide additives did not have catalytic activity for partial oxidation of C3H6 nor for NO oxidation to NO2, except CeO2. The main promotion effect was attributed to storage and release of surface carboxylates by metal oxide additives.

DOI： 10.1016/j.cattod.2017.07.026

Direct Synthesis of Lactams from Keto Acids, Nitriles, and H2 by Heterogeneous Pt Catalysts

S. M.A.H. Siddiki, Abeda S. Touchy, Ashvini Bhosale, Takashi Toyao, Yuji Mahara, Junya Ohyama, Atsushi Satsuma, Ken-Ichi Shimizu

ChemCatChem 10 巻 ( 4 ) 頁： 789 - 795 2018年2月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Wiley Blackwell

We report herein the first general catalytic system for the direct synthesis of N-substituted γ- and δ-lactams by reductive amination/cyclization of keto acids (including levulinic acid) with nitriles and H2 under mild conditions (7 bar H2, 110 °C, solvent free). The most effective catalyst, Pt and MoOx co-loaded TiO2 (Pt-MoOx/TiO2), shows a wide substrate scope, high turnover number (TON), and good reusability.

DOI： 10.1002/cctc.201701355

Dynamic Behavior of Rh Species in Rh/Al<inf>2</inf>O<inf>3</inf> Model Catalyst during Three-Way Catalytic Reaction: An Operando X-ray Absorption Spectroscopy Study

Hiroyuki Asakura, Saburo Hosokawa, Toshiaki Ina, Kazuo Kato, Kiyofumi Nitta, Kei Uera, Tomoya Uruga, Hiroki Miura, Tetsuya Shishido, Junya Ohyama, Atsushi Satsuma, Katsutoshi Sato, Akira Yamamoto, Satoshi Hinokuma, Hiroshi Yoshida, Masato Machida, Seiji Yamazoe, Tatsuya Tsukuda, Kentaro Teramura, Tsunehiro Tanaka

Journal of the American Chemical Society 140 巻 ( 1 ) 頁： 176 - 184 2018年1月

記述言語：英語掲載種別：研究論文（学術雑誌）

© 2017 American Chemical Society. The dynamic behavior of Rh species in 1 wt% Rh/Al2O3 catalyst during the three-way catalytic reaction was examined using a micro gas chromatograph, a NOx meter, a quadrupole mass spectrometer, and time-resolved quick X-ray absorption spectroscopy (XAS) measurements at a public beamline for XAS, BL01B1 at SPring-8, operando. The combined data suggest different surface rearrangement behavior, random reduction processes, and autocatalytic oxidation processes of Rh species when the gas is switched from a reductive to an oxidative atmosphere and vice versa. This study demonstrates an implementation of a powerful operando XAS system for heterogeneous catalytic reactions and its importance for understanding the dynamic behavior of active metal species of catalysts.

DOI： 10.1021/jacs.7b07114

Reductive Conversion of 5-Hydroxymethylfurfural in Aqueous Solutions by Furan Ring Opening and Rearrangement

Ohyama Junya, Satsuma Atsushi

PRODUCTION OF BIOFUELS AND CHEMICALS WITH BIFUNCTIONAL CATALYSTS 頁： 159-185 2017年12月

The Metal–Support Interaction Concerning the Particle Size Effect of Pd/Al<inf>2</inf>O<inf>3</inf> on Methane Combustion

Murata K., Mahara Y., Ohyama J., Yamamoto Y., Arai S., Satsuma A.

Angewandte Chemie - International Edition 56 巻 ( 50 ) 頁： 15993 - 15997 2017年12月

記述言語：日本語掲載種別：研究論文（学術雑誌）出版者・発行元：Angewandte Chemie - International Edition

The particle size effect of Pd nanoparticles supported on alumina with various crystalline phases on methane combustion was investigated. Pd/θ, α-Al2O3 with weak metal-support interaction showed a volcano-shaped dependence of the catalytic activity on the size of Pd particles, and the catalytic activity of the strongly interacted Pd/γ-Al2O3 increased with the particle size. Based on a structural analysis of Pd nanoparticles using CO adsorption IR spectroscopy and spherical aberration-corrected scanning/transmission electron microscopy, the dependence of catalytic activity on Pd particle size and the alumina crystalline phase was due to the fraction of step sites on Pd particle surface. The difference in fraction of the step site is derived from the particle shape, which varies not only with Pd particle size but also with the strength of metal–support interaction. Therefore, this interaction perturbs the particle size effect of Pd/Al2O3 for methane combustion.

DOI： 10.1002/anie.201709124

In Situ XAFS Study of Dynamic Behavior of Cu Species in MFI-Zeolite under Element Gases of Ammonia Selective Catalytic Reduction 査読有り

Kakuya Ueda, Junya Ohyama, Atsushi Satsuma

CHEMISTRY LETTERS 46 巻 ( 9 ) 頁： 1390 - 1392 2017年9月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：CHEMICAL SOC JAPAN

We studied the dynamic redox behavior of Cu species in zeolite matrix under NH3-SCR using in situ XAFS. Cu2+ species were slowly reduced to Cu+ in flowing NH3, and subsequent addition of NO promoted the reduction to Cu+. In the oxidation step, oxygen alone did not fully oxidize Cu+ to Cu2+, but the Cu+ species were completely oxidized to Cu2+ by NO-O-2. The oxidation step was slower than the reduction step, which suggested that the oxidation step (Cu+ -> Cu2+) is the slow step of the NH3-SCR reaction.

DOI： 10.1246/cl.170451

Investigation of Reaction Mechanism of NO-C<inf>3</inf>H<inf>6</inf>-CO-O<inf>2</inf> Reaction over NiFe<inf>2</inf>O<inf>4</inf> Catalyst

Ueda K., Ohyama J., Satsuma A.

ACS Omega 2 巻 ( 7 ) 頁： 3135 - 3143 2017年7月

記述言語：日本語掲載種別：研究論文（学術雑誌）出版者・発行元：ACS Omega

To elucidate the reaction mechanism of NO-C3H6-CO-O2 over NiFe2O4, we investigated the dynamics of the adsorbed and gaseous species during the reaction using operando Fourier transform infrared (FTIR). The NO reduction activity dependent on the C3H6 and CO concentrations suggested that NO is reduced by C3H6 under three-way catalytic conditions. From FTIR measurements and kinetic analysis, it was clarified that the acetate species reacted with NO-O2 to form N2 via NCO, and that the rate-limiting step of NO reduction was the reaction between CH3COO- and NO-O2. The NO reduction mechanism of the three-way catalyst on NiFe2O4 is different to that on platinum-group metal catalysts, on which NO reduction proceeds through N-O cleavage.

DOI： 10.1021/acsomega.7b00165

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