Photoreduction mechanism undelying laser-induced particle formation of metal ion complexes

2022 Fiscal Year Final Research Report

• Project/Area Number: 20K05426
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 32010:Fundamental physical chemistry-related
• Research Institution: National Institutes for Quantum Science and Technology
• Principal Investigator: Nakanishi Ryuzo 国立研究開発法人量子科学技術研究開発機構, 高崎量子応用研究所 東海量子ビーム応用研究センター, 主幹研究員 (70447324)
• Project Period (FY): 2020-04-01 – 2023-03-31
• Keywords: レーザー光還元 / 微粒子化反応 / エネルギー分散型XAFS / 量子化学計算

Outline of Final Research Achievements

Laser-induced particle formation has opened up a unique approach for synthesizing various types of metal particles; pulsed laser irradiation effectively reduces metal ions to neutral atoms and induces the growth of embryonic particles. However, the photochemical reaction mechanism underlying these processes remains unclear. To address this gap, we investigated the kinetics and dynamics of the laser-induced processes involving noble metal ions such as Rh, Pd, and Au by employing time-resolved energy-dispersive XAFS(DXAFS) and quantum chemical calculations. In situ measurements of DXAFS allowed us to trace the electronic and structural changes of metal precursors during the photoreduction. Our results revealed that the new reaction pathways and the reaction intermediates are involved in each reaction system, providing insights into the intricate details of the reaction processes.

Free Research Field

レーザー物理化学

Academic Significance and Societal Importance of the Research Achievements

レーザー光誘起微粒子化における金属錯イオンの光還元について実験・理論の両面からその反応機構の解明に取り組み、ロジウム・パラジウム・金が関与する光還元反応について、提唱されていた反応機構を検証するとともに、新たな反応経路を提唱した。金属錯イオンの液相光還元は微粒子合成、金属回収、触媒表面修飾に使われている手法であり、詳細な反応機構研究は新規な微粒子生成法や金属分離・回収法の開発に繋がると期待される。