研究者詳細 - 永岡　勝俊

論文 - 永岡　勝俊

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Surface Dynamics for Creating Highly Active Ru Sites for Ammonia Synthesis: Accumulation of a Low-Crystalline, Oxygen-Deficient Nanofraction 査読有り

Sato Katsutoshi, Miyahara Shin-ichiro, Ogura Yuta, Tsujimaru Kotoko, Wada Yuichiro, Toriyama Takaaki, Yamamoto Tomokazu, Matsumura Syo, Nagaoka Katsutoshi

ACS SUSTAINABLE CHEMISTRY & ENGINEERING 8 巻 ( 7 ) 頁： 2726 - 2734 2020年2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 Sustainable Chemistry and Engineering

To mitigate global problems related to energy and global warming, it is helpful to develop an ammonia synthesis process using catalysts that are highly active under mild conditions. Here we show that the ammonia synthesis activity per weight of catalyst of Ru/Ba/LaCeOx, prereduced at 700 °C, is the highest among reported oxide-supported Ru catalysts, 52.3 mmol h-1 gcat-1 at 350 °C, 1.0 MPa. The turnover frequency of Ru/Ba/LaCeOx at 350 °C was more than 8 times that of Cs+/Ru/MgO, which is a well-known active catalyst used as a benchmark; furthermore, hydrogen poisoning, a typical drawback for oxide-supported Ru catalysts, was effectively suppressed. Scanning transmission electron microscopy observations with energy dispersive X-ray spectrometry and electron energy loss spectroscopy analysis revealed that a low-crystalline, oxygen-deficient nanofraction including Ba2+, Ce3+, and La3+ had accumulated on the Ru particles. This unique structure was obtained by exploiting the surface dynamics of alkaline earth compounds and thermostable rare earth oxides that contain redox-active atoms during the reduction at an unusually high temperature. The nanofraction showed strong electron-donating ability because of the strong basicity of the included cations, removal of carbonate, and formation of oxygen defect sites that eliminated electron-withdrawing O2- anions from the interface between the nanofraction and Ru atom. Electrons were therefore effectively donated to antibonding π -orbitals of the N2 molecules via Ru in contact with the nanofraction, and NN triple bond cleavage, which is the rate-determining step for ammonia synthesis, was promoted.

DOI： 10.1021/acssuschemeng.9b06299

Kinetics of ammonia synthesis over Ru/Pr2O3 査読有り

Imamura Kazuya, Miyahara Shin-ichiro, Kawano Yukiko, Sato Katsutoshi, Nakasaka Yuta, Nagaoka Katsutoshi

JOURNAL OF THE TAIWAN INSTITUTE OF CHEMICAL ENGINEERS 105 巻頁： 50 - 56 2019年12月

記述言語：日本語掲載種別：研究論文（学術雑誌）

We investigated the kinetics of NH3 synthesis over a catalyst consisting of low-crystalline Ru nano-layers supported on Pr2O3. We determined the reaction orders with respect to N2, H2, and NH3 at various temperatures and pressures over Ru/Pr2O3, as well as Ru/CeO2 and Ru/MgO. The reaction orders with respect to N2 were always almost unity for all the catalysts under all the reaction conditions, indicating that the rate-determining step was NN bond cleavage. In contrast, the reaction orders with respect to H2 differed among the catalysts and decreased with increasing pressure and increased with increasing temperature. Under all conditions, the reaction order with respect to H2 was largest over Ru/Pr2O3 and smallest over Ru/MgO, indicating that hydrogen poisoning of the Ru surface was retarded to a greater extent over Ru/Pr2O3 than over Ru/MgO. In agreement with the trends of the H2 reaction orders, the NH3 synthesis rates over Ru/Pr2O3 at 400 °C rose drastically (64 mmol h−1 g−1) as the pressure was increased from 0.1 to 3.0 MPa. Furthermore, decreasing the feed gas H2/N2 ratio at 3.0 MPa effectively increased the NH3 synthesis rate over Ru/Pr2O3, which reached 45 mmol h−1 g−1 at 350 °C at a H2/N2 ratio of 1/0.5.

DOI： 10.1016/j.jtice.2019.10.006

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Recyclable Rh-PVP nanoparticles catalyzed hydrogenation of benzoic acid derivatives and quinolines under solvent-free conditions 査読有り

Chaudhari Chandan, Imatome Hirotaka, Nishida Yoshihide, Sato Katsutoshi, Nagaoka Katsutoshi

CATALYSIS COMMUNICATIONS 126 巻頁： 55 - 60 2019年6月

Pt-Co Alloy Nanoparticles on a gamma-Al2O3 Support: Synergistic Effect between Isolated Electron-Rich Pt and Co for Automotive Exhaust Purification 査読有り

Sato Katsutoshi, Ito Ayano, Tomonaga Hiroyuki, Kanematsu Homare, Wada Yuichiro, Asakura Hiroyuki, Hosokawa Saburo, Tanaka Tsunehiro, Toriyama Takaaki, Yamamoto Tomokazu, Matsumura Syo, Nagaoka Katsutoshi

CHEMPLUSCHEM 84 巻 ( 5 ) 頁： 447 - 456 2019年5月

Rh/Ce0.25Zr0.75O2 Catalyst for Steam Reforming of Propane at Low Temperature 査読有り

Yu Lin, Sato Katsutoshi, Nagaoka Katsutoshi

CHEMCATCHEM 11 巻 ( 5 ) 頁： 1472 - 1479 2019年3月

A CO Adsorption Site Change Induced by Copper Substitution in a Ruthenium Catalyst for Enhanced CO Oxidation Activity 査読有り国際誌

Huang Bo, Kobayashi Hirokazu, Yamamoto Tomokazu, Toriyama Takaaki, Matsumura Syo, Nishida Yoshihide, Sato Katsutoshi, Nagaoka Katsutoshi, Haneda Masaaki, Xie Wei, Nanba Yusuke, Koyama Michihisa, Wang Fenglong, Kawaguchi Shogo, Kubota Yoshiki, Kitagawa Hiroshi

ANGEWANDTE CHEMIE-INTERNATIONAL EDITION 58 巻 ( 8 ) 頁： 2230 - 2235 2019年2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

Ru is an important catalyst in many types of reactions. Specifically, Ru is well known as the best monometallic catalyst for oxidation of carbon monoxide (CO) and has been practically used in residential fuel cell systems. However, Ru is a minor metal, and the supply risk often causes violent fluctuations in the price of Ru. Performance-improved and cost-reduced solid-solution alloy nanoparticles of the Cu-Ru system for CO oxidation are now presented. Over the whole composition range, all of the Cu x Ru 1−x nanoparticles exhibit significantly enhanced CO oxidation activities, even at 70 at % of inexpensive Cu, compared to Ru nanoparticles. Only 5 at % replacement of Ru with Cu provided much better CO oxidation activity, and the maximum activity was achieved by 20 at % replacement of Ru by Cu. The origin of the high catalytic performance was found as CO site change by Cu substitution, which was investigated using in situ Fourier transform infrared spectra and theoretical calculations.

DOI： 10.1002/anie.201812325

Preparation of Noble-metal Nanoparticles by Microwave-assisted Chemical Reduction and Evaluation as Catalysts for Nitrile Hydrogenation under Ambient Conditions

Nishida Yoshihide, Wada Yuichiro, Chaudhari Chandan, Sato Katsutoshi, Nagaoka Katsutoshi

JOURNAL OF THE JAPAN PETROLEUM INSTITUTE 62 巻 ( 5 ) 頁： 220 - 227 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：Journal of the Japan Petroleum Institute

Herein, we report a protocol for rapid preparation of uniformly sized Ru, Rh, Pd, Ir, and Pt nanoparticles stabilized by poly(N-vinyl-2-pyrrolidone) via microwave-assisted chemical reduction with ethanol. Although the boiling point of ethanol, which has high reduction ability, is much lower than the temperature required for metal cation reduction, this solvent could be used as a reductant because the preparation was carried out in a sealed vessel. All metal nanoparticles showed similar sizes and amounts of poly(N-vinyl-2-pyrrolidone). The crystallite size of the Pd and Pt nanoparticles could be controlled by changing the ethanol concentration. The catalytic performance of the prepared metal nanoparticles was evaluated for the hydrogenation of benzonitrile under ambient conditions (25 °C, 1 bar H2). Rh nanoparticles showed the highest benzonitrile conversion and highest selectivity for secondary imine product. Interestingly, the particle-size dependence of the catalytic activity of the Rh nanoparticles showed volcano-type behavior; that is, the second smallest Rh nanoparticles (3.3 nm) showed the highest activity, which was attributed to high metal surface area and high turnover frequency. Notably, this is the first report of nitrile hydrogenation to afford a secondary imine under ambient conditions.

DOI： 10.1627/jpi.62.220

マイクロ波液相還元法によって調製した Rh ナノ粒子の局所的な配位構造の解析査読有り

西田吉秀, 和田雄一郎, 佐藤勝俊, 永岡勝俊

日本電磁波エネルギー応用学会論文誌 3 巻 ( 0 ) 頁： 1 - 5 2019年

Ru/La0.5Pr0.5O1.75 Catalyst for Low-Temperature Ammonia Synthesis 査読有り

Ogura Yuta, Tsujimaru Kotoko, Sato Katsutoshi, Miyahara Shin-ichiro, Toriyama Takaaki, Yamamoto Tomokazu, Matsumura Syo, Nagaoka Katsutoshi

ACS SUSTAINABLE CHEMISTRY & ENGINEERING 6 巻 ( 12 ) 頁： 17258 - 17266 2018年12月

Combined theoretical and experimental studies of CO oxidation on PdRu nanoalloys 査読有り

Zulkifli Nor Diana Bt., Ishimoto Takayoshi, Sato Katsutoshi, Eboshi Takaaki, Nagaoka Katsutoshi, Koyama Michihisa

APPLIED CATALYSIS A-GENERAL 568 巻頁： 176 - 182 2018年11月

Photocatalytic chemoselective cleavage of C-O bonds under hydrogen gas- and acid-free conditions

Imamura Kazuya, Kato Hiroko, Wada Yuichiro, Makabe Kazuhiro, Onda Ayumu, Tanaka Atsuhiro, Kominami Hiroshi, Sato Katsutoshi, Nagaoka Katsutoshi

CHEMICAL COMMUNICATIONS 54 巻 ( 53 ) 頁： 7298 - 7301 2018年7月

Selective Hydrogenation of Nitriles to Secondary Imines over Rh-PVP Catalyst under Mild Conditions

Nishida Yoshihide, Chaudhari Chandan, Imatome Hirotaka, Sato Katsutoshi, Nagaoka Katsutoshi

CHEMISTRY LETTERS 47 巻 ( 7 ) 頁： 938 - 940 2018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：公益社団法人日本化学会

© 2018 The Chemical Society of Japan. Various metal nanoparticle catalysts (Ru, Rh, Pd, Ir, and Pt) were prepared via liquid-phase reduction and their activity was studied for selective hydrogenation of benzonitrile to corresponding secondary imine under mild conditions (3bar H2and 30°C). The Rh catalyst with particle size of 2.7 nm exhibited excellent activity for the hydrogenation of benzonitrile to secondary imine. The catalyst was reused and applied to transform various nitriles to corresponding secondary imines.

DOI： 10.1246/cl.180349

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Influence of the Crystal Structure of Titanium Oxide on the Catalytic Activity of Rh/TiO2 in Steam Reforming of Propane at Low Temperature 査読有り

Yu Lin, Sato Katsutoshi, Toriyama Takaaki, Yamamoto Tomokazu, Matsumura Syo, Nagaoka Katsutoshi

CHEMISTRY-A EUROPEAN JOURNAL 24 巻 ( 35 ) 頁： 8742-8746 2018年6月

Efficient ammonia synthesis over a Ru/La0.5Ce0.5O1.75 catalyst pre-reduced at high temperature

Ogura Yuta, Sato Katsutoshi, Miyahara Shin-ichiro, Kawano Yukiko, Toriyama Takaaki, Yamamoto Tomokazu, Matsumura Syo, Hosokawa Saburo, Nagaoka Katsutoshi

CHEMICAL SCIENCE 9 巻 ( 8 ) 頁： 2230 - 2237 2018年2月

記述言語：日本語掲載種別：研究論文（学術雑誌）

© 2018 The Royal Society of Chemistry. Ammonia is an important feedstock for producing fertiliser and is also a potential energy carrier. However, the process currently used for ammonia synthesis, the Haber-Bosch process, consumes a huge amount of energy; therefore the development of new catalysts for synthesising ammonia at a high rate under mild conditions (low temperature and low pressure) is necessary. Here, we show that Ru/La0.5Ce0.5O1.75pre-reduced at an unusually high temperature (650 °C) catalysed ammonia synthesis at extremely high rates under mild conditions; specifically, at a reaction temperature of 350 °C, the rates were 13.4, 31.3, and 44.4 mmol g-1h-1at 0.1, 1.0, and 3.0 MPa, respectively. Kinetic analysis revealed that this catalyst is free of hydrogen poisoning under the conditions tested. Electron energy loss spectroscopy combined with O2absorption capacity measurements revealed that the reduced catalyst consisted of fine Ru particles (mean diameter < 2.0 nm) that were partially covered with partially reduced La0.5Ce0.5O1.75and were dispersed on a thermostable support. Furthermore, Fourier transform infrared spectra measured after N2addition to the catalyst revealed that N2adsorption on Ru atoms that interacted directly with the reduced La0.5Ce0.5O1.75weakened the NN bond and thus promoted its cleavage, which is the rate-determining step for ammonia synthesis. Our results indicate that high-temperature pre-reduction of this catalyst, which consists of Ru supported on a thermostable composite oxide with a cubic fluorite structure and containing reducible cerium, resulted in the formation of many sites that were highly active for N2reduction by hydrogen.

DOI： 10.1039/c7sc05343f

Facile Synthesis of Size-controlled Rh Nanoparticles via Microwave-assisted Alcohol Reduction and Their Catalysis of CO Oxidation

Nishida Yoshihide, Sato Katsutoshi, Yamamoto Tomokazu, Wu Dongshuang, Kusada Kohei, Kobayashi Hirokazu, Matsumura Syo, Kitagawa Hiroshi, Nagaoka Katsutoshi

CHEMISTRY LETTERS 46 巻 ( 8 ) 頁： 1254 - 1257 2017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：公益社団法人日本化学会

Size-controlled Rh nanoparticles stabilized by poly(vinylpyrrolidone) were quickly synthesized via alcohol reduction. Microwave-assisted synthesis in closed vessels allowed alcohols with low-to-high boiling points to be used as reductants under the same preparation conditions. Pure ethanol has not been used previously because its boiling point is lower than the temperature required for Rh3+ reduction. Alcohols with relatively strong reduction ability were found to lead to smaller Rh nanoparticles. The ability to oxidize CO was enhanced as the Rh particle size decreased.

DOI： 10.1246/cl.170440

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Solid-Solution Alloying of Immiscible Ru and Cu with Enhanced CO Oxidation Activity 査読有り

Huang Bo, Kobayashi Hirokazu, Yamamoto Tomokazu, Matsumura Syo, Nishida Yoshihide, Sato Katsutoshi, Nagaoka Katsutoshi, Kawaguchi Shogo, Kubota Yoshiki, Kitagawa Hiroshi

JOURNAL OF THE AMERICAN CHEMICAL SOCIETY 139 巻 ( 13 ) 頁： 4643 - 4646 2017年4月

Carbon-free H-2 production from ammonia triggered at room temperature with an acidic RuO2/gamma-Al2O3 catalyst 査読有り

Nagaoka Katsutoshi, Eboshi Takaaki, Takeishi Yuma, Tasaki Ryo, Honda Kyoko, Imamura Kazuya, Sato Katsutoshi

SCIENCE ADVANCES 3 巻 ( 4 ) 頁： e1602747 2017年4月

Supported Ni catalysts prepared from hydrotalcite-like compounds for the production of hydrogen by ammonia decomposition 査読有り

Sato Katsutoshi, Abe Naruhiko, Kawagoe Takafumi, Miyahara Shin-ichiro, Honda Kyoko, Nagaoka Katsutoshi

INTERNATIONAL JOURNAL OF HYDROGEN ENERGY 42 巻 ( 10 ) 頁： 6610 - 6617 2017年3月

Electronic Structure Evolution with Composition Alteration of RhxCuy Alloy Nanoparticles

Palina Natalia, Sakata Osami, Kumara L. S. R., Song Chulho, Sato Katsutoshi, Nagaoka Katsutoshi, Komatsu Tokutaro, Kobayashi Hirokazu, Kusada Kohei, Kitagawa Hiroshi

SCIENTIFIC REPORTS 7 巻 ( 7 ) 頁： 41264 2017年1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：Springer Nature

組成が違っても触媒活性が同等な新規Rh-Cuナノ粒子の電子状態の観測 : 合金の複合的な電子状態が寄与することを示唆. 京都大学プレスリリース. 2017-01-30.

DOI： 10.1038/srep41264

A low-crystalline ruthenium nano-layer supported on praseodymium oxide as an active catalyst for ammonia synthesis 査読有り

Sato Katsutoshi, Imamura Kazuya, Kawano Yukiko, Miyahara Shin-ichiro, Yamamoto Tomokazu, Matsumura Syo, Nagaoka Katsutoshi

CHEMICAL SCIENCE 8 巻 ( 1 ) 頁： 674 - 679 2017年1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：Royal Society of Chemistry (RSC)

Ammonia is a crucial chemical feedstock for fertilizer production and is a potential energy carrier. However, the current method of synthesizing ammonia, the Haber–Bosch process, consumes a great deal of energy. To reduce energy consumption, a process and a substance that can catalyze ammonia synthesis under mild conditions (low temperature and low pressure) are strongly needed. Here we show that Ru/Pr2O3 without any dopant catalyzes ammonia synthesis under mild conditions at 1.8 times the rates reported with other highly active catalysts. Scanning transmission electron micrograph observations and energy dispersive X-ray analyses revealed the formation of low-crystalline nano-layers of ruthenium on the surface of Pr2O3. Furthermore, CO2 temperature-programmed desorption revealed that the catalyst was strongly basic. These unique structural and electronic characteristics are considered to synergistically accelerate the rate-determining step of NH3 synthesis, cleavage of the N[triple bond, length as m-dash]N bond. We expect that the use of this catalyst will be a starting point for achieving efficient ammonia synthesis.

DOI： 10.1039/c6sc02382g

その他リンク： http://orcid.org/0000-0003-1774-1537

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