Creation of highly efficient electrocatalysts for acidic water electrolysis using complex metal complex crystals

2023 Fiscal Year Final Research Report

• Project/Area Number: 21K05260
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 36020:Energy-related chemistry
• Research Institution: Kyushu Institute of Technology
• Principal Investigator: Takase Satoko 九州工業大学, 大学院工学研究院, 助教 (60239275)
• Project Period (FY): 2021-04-01 – 2024-03-31
• Keywords: 水電解 / 電極触媒 / 導電性錯体結晶

Outline of Final Research Achievements

To develop a catalyst for acidic water electrolysis cells, we investigated a method for controlling the molecular arrangement in molecular crystals of metal phthalocyanine complexes, which have a structure similar to the active site of water-splitting enzymes and acid resistance, and the relationship between molecular arrangement and catalytic properties.Based on the method of dropping organic solutions of water-insoluble complexes into aqueous solutions, solution compositions were investigated, and various metal complex crystals and charge transfer complex crystals combined with acceptor species were successfully obtained.
The results of catalytic characterization of these complexes showed that the charge-transfer complexes combining closely arranged molecular columns with orbital energy bands and acceptor species with high electronegativity exhibit high catalytic activity for hydrogen generation.It was also examined as a hydrogen supply mechanism for the CO2 reduction reaction.

Free Research Field

電気化学

Academic Significance and Societal Importance of the Research Achievements

電気化学的水分解を生物の中で進める酵素は、マンガンなど安価な金属の錯体を活性点とするが、再生可能エネルギー発電を蓄電するための水電解のようなエネルギー変換デバイスに触媒として利用するには導電性、活性点密度、化学的安定性が低い。これらの課題を解決するために、酵素活性部位に類似し化学的に安定な錯体種の中で自己集積しやすい平面分子の分子結晶を触媒とすることで、活性点密度向上と化学的安定性を改善し、さらに錯体分子結晶内に電気陰性度が高いアクセプターイオンを共存させることで導電性を改善した。得られた触媒が水素生成活性向上を示したことは、錯体触媒設計指針の拡張に寄与する。