2022 Fiscal Year Final Research Report

Development of oxygen evolution catalysts with high intrinsic activity and stability by exploring the compounds with strong electron-electron correlation within the d-orbital

Research Project

PDF

Project/Area Number	20H02831
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	Kitami Institute of Technology
Principal Investigator	Hirai Shigeto 北見工業大学, 工学部, 准教授 (80756669)
Co-Investigator(Kenkyū-buntansha)	八木俊介東京大学, 生産技術研究所, 准教授 (60452273) 大野智也北見工業大学, 工学部, 教授 (90397365)
Project Period (FY)	2020-04-01 – 2023-03-31
Keywords	酸素発生反応 / 酸性電解液 / 二元機能 / 表面構造 / 高活性 / 高耐久性 / 溶出 / イリジウム
Outline of Final Research Achievements	We have achieved the initial research goal to develop a bifunctional catalyst toward oxygen evolution reaction(OER) with both high intrinsic activity and stability by preventing the lattice collapse after repeated OER cycling even if the catalyst is under acidic conditions, which is known to be the most harsh condition. Specifically, we found that the substitution of Ir-site with Mn for BaIrO3 leads to a remarkably high intrinsic activity and stability toward OER. This excellent OER performance was achieved by slightly increasing the Ir-dissolution and balancing the elemental dissolution in BaIr1-xMnxO3 to maintain the initial surface structure that reflects the OER stable crystal structure of BaIr1-xMnxO3. Since BaIr1-xMnxO3 is equipped with both high OER activity and stability under acidic conditions, it has brought a big impact leading to possible application as an electrode for energy conversion technologies.
Free Research Field	エネルギー関連化学
Academic Significance and Societal Importance of the Research Achievements	水の電気分解セルや金属空気二次電池の電極に搭載できるレベルの酸素発生(OER)触媒を開発できれば、水素燃料の製造や電気自動車の実用化につながる。しかし、そのためには高い初期活性とともに、高い安定性をもった触媒が必須であるが、多数サイクルのOERで触媒表面の組成が変化してしまい、OERに対して安定な表面構造が保てず、最終的には安定性が低下するという長年の課題が存在した。本研究ではBaIrO3のIrサイトをMnで置換することで、この難題の解決に成功しただけでなく、そのベースとなる反応機構を解明したため、電気化学の発展とともに、水素燃料の製造や電気自動車の実用化に直結した成果が得られたと言える。