Catalytic degradation mechanism of noble metal nanoparticles on metal oxides

2022 Fiscal Year Final Research Report

• Project/Area Number: 20K21073
• Research Category: Grant-in-Aid for Challenging Research (Exploratory)
• Allocation Type: Multi-year Fund
• Review Section: Medium-sized Section 26:Materials engineering and related fields
• Research Institution: The University of Tokyo
• Principal Investigator: Ishikawa Ryo 東京大学, 大学院工学系研究科(工学部), 特任准教授 (20734156)
• Project Period (FY): 2020-07-30 – 2023-03-31
• Keywords: 貴金属ナノ触媒 / 原子分解能電子顕微鏡法

Outline of Final Research Achievements

We have investigated the degradation mechanism of catalytic activity in Pt-nanoparticles (NPs) on TiO2 (110) substrate using atomic-resolution scanning transmission electron microscopy combined with in-situ heating in the electron microscope. We found that the Pt-NPs were grown by heating, transforming the NPs into Pt-Ti intermetallic NPs. Furthermore, the Pt-Ti intermetallic NPs were embedded into the TiO2 (110) substrate. It has been reported that the surface of Pt-NP is covered with TiOx thin film by heating. However, there was no oxide coverage in the electron energy-loss spectroscopy. It is therefore revealed that the catalyst degradation is caused by (1) a change in the interfacial bonding state due to the alloying of Pt-Ti, and (2) the coverage of active sites by the intrusion of the TiO2 (110) substrate.

Free Research Field

材料工学

Academic Significance and Societal Importance of the Research Achievements

弱い還元雰囲気（高真空）ではあるものの，加熱によりPtナノ粒子の挙動を原子レベルで初めて明らかにした．また，ナノ粒子の合金化や基板への侵入は直接観察による報告例はなく，学術的にも重要な結果である．得られた結果を基礎として，合金化や基板への侵入を抑制した系を考えることにより，新たな触媒設計が可能となり，社会的貢献が期待される．