Observation of carrier dynamics in powder photocatalysts under magnetic field and its application

2022 Fiscal Year Final Research Report

• Project/Area Number: 20K15386
• Research Category: Grant-in-Aid for Early-Career Scientists
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 36020:Energy-related chemistry
• Research Institution: Okayama University (2022); Toyota Technological Institute (2020-2021)
• Principal Investigator: KATO Kosaku 岡山大学, 自然科学研究科, 技術職員 (40751087)
• Project Period (FY): 2020-04-01 – 2023-03-31
• Keywords: 光触媒 / キャリアダイナミクス / 過渡吸収

Outline of Final Research Achievements

We studied photocarrier dynamics in photocatalysts using transient absorption spectroscopy. The experimental results suggested that defects on powder particle surfaces have dualistic properties of accelerating and decelerating electron－hole pair recombination, and which property becomes dominant is determined by the distribution of the defects. On the other hand, to investigate the origin of the previously reported effects of magnetic field on photocatalytic activities, we measured the photocarrier lifetime of photocatalysts under magnetic field. The sample was set in a cell between the gap of the electromagnet, and the transient absorption in the presence and absence of external magnetic field was compared. However, we could not find a significant effect of magnetic field on photocarrier lifetime, which suggests that magnetic field affects more strongly on the reactions of molecules after receiving photocarriers than on photocarrier dynamics inside photocatalysts.

Free Research Field

レーザー分光

Academic Significance and Societal Importance of the Research Achievements

光触媒を用いると，水と太陽光を用いてクリーンなエネルギー源である水素を生成したり，大気や水質の汚染物質を分解したりすることが可能で，様々な環境問題の解決策として近年大きく注目されている．本研究で過渡吸収分光測定を通して得られた新たな知見は，将来のより高活性な光触媒の開発において基礎となる，光触媒中における光励起キャリアのダイナミクスについての理解を深める上で有用であると考えられる．