Study on surface chemical reactions by real-time tracing with atomic-resolution microscope and x-ray spectroscopy

原子分辨率显微镜和X射线光谱实时追踪研究表面化学反应

基本信息

批准号：
17205002
负责人：
KONDOH Hiroshi
金额：
$ 30.78万
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 (A)
财政年份：
2005
资助国家：
日本
起止时间：
2005 至 2007
项目状态：
已结题

项目摘要

The aim of this project is developing a combined approach of spatial distribution of surface species obtained from microscopic techniques and kinetics information provided from synchrotron-based spectroscopies and reaction simulations to understand the mechanisms of surface reactions proceeding on solid surfaces and its application to mechanistic studies on actual surface reactions. The mechanistic studies on the basis of this approach revealed the microscopic mechanisms for several important surface processes as shown below and led to confirm its usefulness.1. CO oxidation Pt(111), which is a model reaction for the automobile catalysis, exhibits a significant decrease in reaction rate when surface oxygen atoms form two-dimensional islands. It was clarified that this rate reduction is caused by strong destabilization of the transition state for oxidation of CO molecules inside the islands due to large repulsive interactions with neighbor CO molecules.2. For NO reduction on Rh(111), which is a model reaction for the automobile catalysis, we found a new reaction path where impinging NO molecules from gas phase form a NO dimer and react with surface nitrogen. It was revealed that attack of the NO dimer to surface nitrogen with N-N bond facing to the surface plays a key role in this reaction.3. Proton transfer at surfaces, which is considered to act an important role on the Pt fuel-cell catalysts, was studied using H_2O+OH overlayers on Pt(111). As a result, we found not only the simple proton transfer from H_2O to OH but also significant contribution of proton transfer via formation of H_3O+ to the next-nearest OH site. We also estimated the time scale of the two proton transfer processes for the first time.

该项目的目的是开发一种从基于同步加速器的光谱和反应模拟提供的微观技术和动力学信息获得的表面物种的空间分布的合并方法，以了解在固体表面上进行表面反应的机制，以及其在实际表面反应上应用于机械性研究。基于该方法的机械研究揭示了几种重要的表面过程的微观机制，如下所示，并确认了其有用性。1。 CO氧化Pt（111）是汽车催化的模型反应，当表面氧原子形成二维岛时，反应速率显着降低。可以澄清的是，这种降低是由于与邻居CO分子的较大排斥性相互作用而导致的岛内CO分子氧化的强烈不稳定。对于RH（111）的降低（111）是汽车催化的模型反应，我们发现了一个新的反应路径，在该方案中，撞击气相没有分子形成无二聚体并与表面氮反应。据揭示，没有二聚体对表面面向表面的表面氮的攻击在该反应中起关键作用。3。在PT上使用H_2O+OH叠加剂研究了在PT燃料细胞催化剂上起重要作用的表面质子转移（111）。结果，我们不仅发现了从H_2O到OH的简单质子转移，而且还通过形成H_3O+向下一个最新的OH位点进行了质子转移的显着贡献。我们还首次估算了两个质子传输过程的时间尺度。