Development of ambient-pressure ultrasoft x-ray surface XAFS and application to operando observation of catalytic reactions under ambient pressure conditions

2020 Fiscal Year Final Research Report

• Project/Area Number: 18K19064
• Research Category: Grant-in-Aid for Challenging Research (Exploratory)
• Allocation Type: Multi-year Fund
• Review Section: Medium-sized Section 32:Physical chemistry, functional solid state chemistry, and related fields
• Research Institution: Keio University
• Principal Investigator: Kondoh Hiroshi 慶應義塾大学, 理工学部(矢上), 教授 (80302800)
• Project Period (FY): 2018-06-29 – 2021-03-31
• Keywords: X線吸収微細構造 / 極端軟X線 / 大気圧 / 触媒・化学プロセス / 表面・界面物性 / 量子ビーム / 化学物理

Outline of Final Research Achievements

Although the ultrasoft x-ray surface XAFS is a useful technique which enables us to obtain information on local geometric and electronic structures of surface species composed of light elements such as carbon, nitrogen and oxygen and the 4th-period metals such as titanium and iron, it has been assumed to be difficult to use this technique under atmospheric conditions.In this study, we aimed to be able to measure ultrasoft x-ray surface XAFS spectra under ambient-pressure conditions based on the conversion electron yield method and successfully developed an apparatus with which we can easily conduct ambient-pressure ultrasoft x-ray surface XAFS measurements.Furthermore we applied this technique to in-situ measurements for several materials under ambient-pressure conditions.

Free Research Field

表面化学

Academic Significance and Societal Importance of the Research Achievements

これまで主に硬Ｘ線領域で用いられてきた転換電子収量法を軽元素や第4周期元素の解析に有効な極端軟Ｘ線領域に導入し、適切な測定セルを用いることで大気圧下の表面XAFSを測定することが簡便にできるようになった。これにより、特にこれまで例が少なった軽元素からなる材料の大気圧下での表面敏感な測定が可能になるので、触媒や機能性材料の機能部位が軽元素で構成される物質表面である場合に、その作動条件下でのその場計測に有効に用いることができる。