Development of 3-d block oxygen evolution catalysts based on new activity prediction model

• Project/Area Number: 18H02070
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Review Section: Basic Section 36020:Energy-related chemistry
• Research Institution: Tokyo Institute of Technology
• Principal Investigator: Nakamura Ryuhei 東京工業大学, 地球生命研究所, 教授 (10447419)
• Project Period (FY): 2018-04-01 – 2021-03-31
• Project Status: Completed (Fiscal Year 2021)
• Budget Amount: ¥17,290,000 (Direct Cost: ¥13,300,000、Indirect Cost: ¥3,990,000); Fiscal Year 2020: ¥5,070,000 (Direct Cost: ¥3,900,000、Indirect Cost: ¥1,170,000); Fiscal Year 2019: ¥5,720,000 (Direct Cost: ¥4,400,000、Indirect Cost: ¥1,320,000); Fiscal Year 2018: ¥6,500,000 (Direct Cost: ¥5,000,000、Indirect Cost: ¥1,500,000)
• Keywords: 水電解 / 酸化マンガン / 水素製造 / マンガン酸化物 / 電極触媒 / 水素エネルギー / 人工光合成 / 電気分解 / 元素戦略 / 水素 / 電子移動

Outline of Final Research Achievements

As a method to introduce structural distortion into Mn oxides, we have studied gamma-type MnO2, which has a microtwinning structure and allows precise control of structural distortion. As a result, it was confirmed that the disproportionation reaction of Mn3+ is suppressed with the introduction of structural distortion, and the overpotential of oxygen evolution is reduced. By optimizing the electrolysis conditions taking into account the potential dependence of the disproportionation reaction, we found that the MnO2 catalyst can stably electrolyze water even in a strong acid environment.

Academic Significance and Societal Importance of the Research Achievements

水の電気分解による水素製造は、CO2排出フリーの化学産業を構築するうえで不可欠である。しかし、酸素発生反応に対して、優れた活性と安定性を持つ触媒は、Irなどの希少金属のみであり、Mnなど豊富に存在する元素を用いた触媒の開発が強く望まれている。同課題の解決するための方法論として、本研究では、「構造歪みの導入によるMn3＋イオンの不均化反応に対する安定性の向上」を提案した。その結果得られた、高い酸耐性を有するMn酸化物触媒は、貴金属を用いない水電解技術の開発につながるものである。

Research Products

• [Journal Article] Enhancing the stability of cobalt spinel oxide towards sustainable oxygen evolution in acid (2022)
  • Author(s): 1.A. Li, S. Kong, C. Guo, H. Ooka, K. Adachi, D. Hashizume, Q. Jiang, H. Han, J. Xiao, R. Nakamura
  • Journal Title: Nat. Catal Volume: 5 Issue: 2 Pages: 109-118
  • DOI: 10.1038/s41929-021-00732-9
  • Peer Reviewed
• [Journal Article] Stable Potential Windows for Long‐Term Electrocatalysis by Manganese Oxides Under Acidic Conditions (2019)
  • Author(s): Li Ailong、Ooka Hideshi、Bonnet Nadege、Hayashi Toru、Sun Yimeng、Jiang Qike、Li Can、Han Hongxian、Nakamura Ryuhei
  • Journal Title: Angewandte Chemie International Edition Volume: 58 Issue: 15 Pages: 5054-5058
  • DOI: 10.1002/anie.201813361
  • Peer Reviewed / Int'l Joint Research
• [Presentation] Energy Conversion with Bio- and Geo-Inspired Catalysts (2019)
  • Author(s): Ryuhei Nakamura
  • Organizer: RIKEN-NCTU Symposium on Physical and Chemical Sciences
  • Int'l Joint Research / Invited
• [Presentation] Progress on Water Splitting by Mn-based Electrocatalysts (2019)
  • Author(s): Ryuhei Nakamura
  • Organizer: The 4th Solar Fuel Material Workshop, September
  • Int'l Joint Research / Invited
• [Patent(Industrial Property Rights)] 水電気分解法及び装置、並びに水電気分解の駆動電位の決定方法 (2019)
  • Inventor(s): 中村龍平 等
  • Industrial Property Rights Holder: 中村龍平 等
  • Industrial Property Rights Type: 特許
  • Filing Date: 2019
  • Overseas