Development of innovative photocatalytic systems for utilizing CO2

2023 Fiscal Year Final Research Report

• Project/Area Number: 20H00396
• Research Category: Grant-in-Aid for Scientific Research (A)
• Allocation Type: Single-year Grants
• Section: 一般
• Review Section: Medium-sized Section 36:Inorganic materials chemistry, energy-related chemistry, and related fields
• Research Institution: Tokyo Institute of Technology
• Principal Investigator: Ishitani Osamu 東京工業大学, 理学院, 教授 (50272282)
• Project Period (FY): 2020-04-01 – 2024-03-31
• Keywords: 光反応化学 / 錯体光触媒 / 半導体光触媒 / 二酸化炭素還元

Outline of Final Research Achievements

We succeeded in developing a new photosensitizer that can utilize all visible light. We clarified the factors that determine the efficiency of the production of one-electron reduced photosensitizers via the reaction of the excited photosensitizers with reductant. The reaction mechanisms of the entire processes of CO2 photocatalytic reduction using Re complex catalysts were clarified.
We could demonstrate that the supramolecular photocatalysts reduce CO2 efficiently even on solid surface. By addition of photosensitizers around the supramolecular photocatalyst, the photocatalytic stability of the supramolecular photocatalysts on the surface were drastically improved. We have succeeded in photocatalytically producing CO, formic acid and hydroperoxide using only water, CO2 and visible light. Hybrid photocatalyst consisting of the supramolecular photocatalyst and conjugated polymer showed the highest CO2 reduction photocatalysis compared to any reported CO2 reduction photocatalytic systems.

Free Research Field

光反応化学

Academic Significance and Societal Importance of the Research Achievements

光増感反応の機能を大幅に向上することが可能になった（可視光全領域の利用、光増感剤の1電子還元種の生成効率の向上）。Re(I)錯体上でのCO2還元機構を明らかにし、各素過程の速度と熱力学的データを収集できたことは、今後、高効率CO2還元光触媒を開発するために貴重な情報となる。超分子光触媒の固体正面における機能を初めて明らかにし、複合系光触媒開発に貴重な情報を与えた。水とCO2からギ酸と過酸化水素を発生させる全く新しい光触媒系の開発に成功した。超分子光触媒と共役ポリマー半導体光触媒のハイブリッドは最も耐久性が高い光触媒であり、水素の前駆液体となる高濃度ギ酸溶液を作ることが可能になった。