Visible light water splitting photocatalyst consisting of metal oxide nanosheets and first-row transition metal oxide nanoparticles

2022 Fiscal Year Final Research Report

• Project/Area Number: 19H02511
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Review Section: Basic Section 27030:Catalyst and resource chemical process-related
• Research Institution: Tokyo Institute of Technology
• Principal Investigator: Maeda Kazuhiko 東京工業大学, 理学院, 教授 (40549234)
• Project Period (FY): 2019-04-01 – 2023-03-31
• Keywords: 人工光合成 / カーボンニュートラル / 水素製造 / 色素増感 / 過渡吸収分光

Outline of Final Research Achievements

A hybrid material consisting of niobate nanosheets and ruthenium(II) complexes was found to act as a photocatalyst for the efficient generation of hydrogen from water under visible light irradiation. Combined with a tungsten trioxide-based photocatalyst for oxygen generation, they succeeded in splitting water into hydrogen and oxygen in the presence of an iodine-based redox agent. The performance of this system varied greatly depending on the type of ruthenium complex, the presence of modifiers such as amorphous alumina, and the synthesis method of niobate nanosheets. Spectroscopy measurements revealed that a photocatalytic design that suppresses the reverse electron transfer to the one-electron oxidizing species of the ruthenium complexes formed during the reaction and maximizes the electron injection efficiency from the excited state ruthenium to the nanosheet is essential for high activity.

Free Research Field

光化学・触媒化学

Academic Significance and Societal Importance of the Research Achievements

これまで、色素増感型光触媒では、色素分子の耐久性や担体酸化物の制約があることから、水の水素と酸素への完全分解が可能な高性能の光触媒を創出することは困難と考えられてきた。今回の一連の研究成果により、精密設計されたナノ材料を色素増感型光触媒の部材として活用することで、太陽光エネルギーを化学エネルギーへ変換する革新的な機能材料を創出できる可能性が見えてきた。今後、可視光吸収を担う色素の分子設計や類似ナノシート材料を検討することで、色素増感型光触媒のさらなる性能向上が見込まれる。結果として本研究成果が、太陽光エネルギー変換を指向した色素増感型光触媒の開発を大きく促進すると期待される。