Auger-Electron-Probe Time-Resolved Surface XAFS Technique and Its Application to Study of Surface Dynamics

俄歇电子探针时间分辨表面XAFS技术及其在表面动力学研究中的应用

基本信息

批准号：
16072205
负责人：
KONDOH Hiroshi
金额：
$ 16.9万
依托单位：
The University of Tokyo
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research on Priority Areas
财政年份：
2004
资助国家：
日本
起止时间：
2004 至 2006
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-16072205/
关键词：
Time resolved XAFS XPS reaction dynamics reaction kinetics reaction mechanism 表面ダイナミクス

项目摘要

We have developed a fast surface x-ray absorption fine structure(XAFS)technique where solid substrates are irradiated by energy-dispersed synchrotron-radiation x rays and auger electrons emitted from x-ray absorbing surface species are collected at once with a spatially resolved way. In this project we aimed further development of this technique and its application to mechanistic studies on chemical reactions on solid substrates. The present improvement enabled us to trace changes in both surface and gas-phase species simultaneously every approximately 1 s. If this technique is applied to repeatable processes, we can detect submonolayer surface species with a time resolution of 10 ms by using a time gate for the detector. Furthermore we extended this technique to the undulator-based time-resolved x-ray photoelectron spectroscopy, which enabled us to observe dynamic processes of submonolayer surface species with a time resolution of 2 ms.Real-time monitoring of surface reaction kinetics based on these techniques provided following three major achievements in research that have never been achieved by previous methods.(1) Finding of a novel reaction pathway involving a NO dimer as a reaction intermediate under the reaction condition of NO reduction on Rh(2) Elucidation of cirrelation between phase transition of surface oxygen and reactivity under the reaction condition of CO oxidation on Pd(3) Detection of a transient high-density adsorption state with a life time of less than millisecond order induced by NO pulsed molecular beamThe present development of the fast observation technique for surface species and its application to surface dynamic processes open a way to study novel dynamic processes that have not been detected with previous static surface techniques.

我们已经开发了一种快速的表面X射线吸收精细结构（XAFS）技术，其中固体底物被能量分散的同步加速器放射X射线和从X射线吸收表面物种发出的螺丝电子辐射照射，并以空间分辨的方式一次收集。在这个项目中，我们旨在进一步开发该技术及其在固体底物上化学反应的机理研究中的应用。目前的改进使我们能够同时每次大约1 s同时追踪表面和气相物种的变化。如果将此技术应用于可重复的过程，我们可以通过使用时间门来检测检测器，以10 ms的时间分辨率检测下层表面物种。此外，我们将此技术扩展到基于波动的时间分辨的X射线光电子光谱谱，这使我们能够观察基于2 MS.ss.ss s.real time在表面反应的表面反应的时间分辨率的时间分辨率的时间分辨率基于这些研究中的三个重大反应后提供的反应以前的反应以前的反应未达到的方法（1）ASS（1）ASS（1）ASS ASS的反应中提供的三个主要成就。在反应条件下，中间体在不减少RH的反应条件下（2）阐明表面氧相位过渡与PD氧化反应条件下的反应条件（3）检测瞬态高密度的吸附状态与持续时间较小的寿命相比，不超过脉冲的表面过程，其脉冲孔的效果较小，并在脉冲上的效果较小，并在脉冲上进行了脉冲孔的发展，并在脉冲上进行了快速的体面，并具有快速的体面的生命。先前静态表面技术尚未检测到的动态过程。