Catalytic degradation mechanism of noble metal nanoparticles on metal oxides
| Project/Area Number |
20K21073
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| Research Category |
Grant-in-Aid for Challenging Research (Exploratory)
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| Allocation Type | Multi-year Fund |
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| Review Section |
Medium-sized Section 26:Materials engineering and related fields
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| Research Institution | The University of Tokyo |
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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)
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| Project Period (FY) |
2020-07-30 – 2023-03-31
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| Project Status |
Completed (Fiscal Year 2022)
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| Budget Amount *help |
¥6,370,000 (Direct Cost: ¥4,900,000、Indirect Cost: ¥1,470,000)
Fiscal Year 2022: ¥1,170,000 (Direct Cost: ¥900,000、Indirect Cost: ¥270,000)
Fiscal Year 2021: ¥1,690,000 (Direct Cost: ¥1,300,000、Indirect Cost: ¥390,000)
Fiscal Year 2020: ¥3,510,000 (Direct Cost: ¥2,700,000、Indirect Cost: ¥810,000)
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| Keywords | 貴金属ナノ触媒 / 原子分解能電子顕微鏡法 / 貴金属ナノ粒子 / 金属間化合物 / 走査透過型電子顕微鏡 / 真空加熱 / TiO2 / 原子分解能電子顕微鏡 |
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| Outline of Research at the Start |
水分解に代表される化学反応あるいは気相反応を利用した新物質合成では，触媒材料の改良や発見が中心的な役割を果たしている．金属ナノ粒子を利用した不均一触媒系では，基板表面の選択や粒径の制御により酸化・還元反応の活性が大幅に改善されたものの，触媒活性の発現・劣化機構は未だ不明である．特に高温での利用により，触媒活性が急激に劣化することが大きな課題である．本研究では，原子分解能を有する走査透過型電子顕微鏡を用い，高温・還元雰囲気下での劣化状態を直接観察することで劣化機構を明らかにすることを目的とする．
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| 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.
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| 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．
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Report
(4 results)
Research Products
(58 results)
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[Journal Article] Direct visualization of anionic electrons in an electride reveals inhomogeneities2021
Author(s)
Q. Zheng, T. Feng, J.A. Hachtel, R. Ishikawa, Y. Cheng, L. Daemen, J. Xing, J.C. Idrobo, J. Yan, N. Shibata, Y. Ikuhara, B.C. Sales, S.T. Pantelides, M. Chi
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Journal Title
Sci. Adv.
Volume: 7
Issue: 15
DOI
Related Report
Peer Reviewed / Open Access / Int'l Joint Research
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