Kyushu University Academic Staff Educational and Research Activities Database
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Kosei Yamauchi Last modified date:2023.05.18

Assistant Professor / Inorganic and Analytical Chemistry
Department of Chemistry
Faculty of Sciences

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Academic Degree
Dr. Sci.
Field of Specialization
Coordination Chemistry
Research Interests
  • Studies on the overall water-splitting and CO2 reduction reactions catalyzed by molecular catalysts
    keyword : H2-evolving catalyst, O2-evolving catalyst, Water-splitting, Hydrogen energy, Metal complexes CO2 reduction
Academic Activities
1. Kosei Yamauchi, Saya Tanaka, Masayuki Kobayashi, Chettiyam Veettil Suneesh, and Ken Sakai, Molecular Systems Driving Photochemical and Thermal H2 Production from Water, Kyushu University Global-COE program Science for Molecular Systems Journal, 2012, 5, 52-55., 2012.03.
1. Keita Kuge, Kosei Yamauchi and Ken Sakai, Theoretical study on the mechanism of the hydrogen evolution reaction catalyzed by platinum subnanoclusters, Dalton Transactions, 10.1039/D2DT02645G, 52, 583-597, 2022.11.
2. Yuto Sakaguchi, Arnau Call, Kosei Yamauchi, Ken Sakai, Catalysis of CO2 reduction by diazapyridinophane complexes of Fe, Co, and Ni: CO2 binding triggered by combined frontier MO associations involving a SOMO, Dalton Transactions, 10.1039/d1dt01877a, 2021.08, The Fe- and Co-based molecular catalysts are found to utilize multiple sets of frontier MO associations at the CO2 binding by including one of the SOMOs in a high-spin Fe(i) and Co(i) center, respectively, accelerating these oxidative addition steps..
3. Xian Zhang, Kosei Yamauchi, Ken Sakai, Earth-Abundant Photocatalytic CO2 Reduction by Multielectron Chargeable Cobalt Porphyrin Catalysts: High CO/H2 Selectivity in Water Based on Phase Mismatch in Frontier MO Association, ACS Catalysis, 10.1021/acscatal.1c02475, 11, 16, 10436-10449, 2021.08.
4. Koichi Yatsuzuka, Kosei Yamauchi, Ken Sakai, Redox tuning in Pt(bpy)-viologen catalyst-acceptor dyads enabling photocatalytic hydrogen evolution from water, Chemical Communications, 10.1039/D1CC00903F, 57, 42, 5183-5186, 2021.05.
5. Koichi Yatsuzuka, Kosei Yamauchi, Ken Kawano, Hironobu Ozawa, Ken Sakai, Improving the overall performance of photochemical H2evolution catalyzed by the Co-NHC complex via the redox tuning of electron relays, Sustainable Energy and Fuels, 10.1039/d0se01597k, 5, 3, 740-749, 2021.02, © The Royal Society of Chemistry 2021. The catalytic performance of a photochemical H2evolution system made up of EDTA (ethylenediaminetetraacetic acid disodium salt), [Ru(bpy)3]2+(bpy = 2,2′-bipyridine) and a macrocyclicN-heterocyclic carbene cobalt (Co-NHC-1) catalyst has been examined at pH 5.0 (E(2H+/H2) = −0.54 Vvs.SCE) by using six electron relays (ERs) having different first reduction potentials (Ered) in the range −0.69
6. Keita Koshiba, Kosei Yamauchi, Ken Sakai, A Nickel Dithiolate Water Reduction Catalyst Providing Ligand-Based Proton-Coupled Electron-Transfer Pathways, Angewandte Chemie - International Edition, 10.1002/anie.201700927, 56, 15, 4247-4251, 2017.03, A nickel pyrazinedithiolate ([Ni(dcpdt)2]2−; dcpdt=5,6-dicyanopyrazine-2,3-dithiolate), bearing a NiS4 core similar to the active center of [NiFe] hydrogenase, is shown to serve as an efficient molecular catalyst for the hydrogen evolution reaction (HER). This catalyst shows effectively low overpotentials for HER (330–400 mV at pH 4–6). Moreover, the turnover number of catalysis reaches 20000 over the 24 h electrolysis with a high Faradaic efficiency, 92–100 %. The electrochemical and DFT studies reveal that diprotonated one-electron-reduced species forms at pH < 6.4 via ligand-based proton-coupled electron-transfer (PCET) pathways, leading to electrocatalytic HER without applying the highly negative potential required to generate low-valent nickel intermediates. This is the first example of catalysts exhibiting such behavior..
1. Kosei Yamauchi, Ken Sakai, PHOTOCHEMICAL HYDROGEN PRODUCTION FROM WATER CATALYZED BY ROBUST MOLECULAR CATALYSTS, 41st International Conference on Coordination Chemistry (ICCC41), 2014.07.
2. Kosei Yamauchi, Ken Sakai, Photochemical Hydrogen Production from Water Promoted by Robust Platinum(II) Molecular Catalysts, 1st International Symposium on Chemical Energy Conversion Processes (ISCECP-1), 2013.07.
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Membership in Academic Society
  • The Chemical Society of Japan (CSJ)
  • Japan Society of Coordination Chemistry
  • The Photofunctional Complexes Research Association, Japan