Research Initiation Award: The Redox State, Composition, andStructure of Reactive Oxide Surfaces: W/M/D Supplement

这是在催化反应中测定金属氧化物催化剂表面层氧化状态的一种尝试。到目前为止，除非在非常不现实的条件下，否则无法获得此类数据。该方法将大气压或近大气压下的瞬态动力学与超高真空下的光谱（特别是俄歇电子光谱）相结合。研究了两种类型的氧化物：在多晶金上生长的单组分和双组分氧化物的厚（微米级）薄膜，以及在单晶金上生长的尖晶石的薄（纳米级）薄膜。利用拉曼光谱和低能电子衍射对薄膜进行了表征。乙醇被用作化学探针；酸碱反应和氧化还原反应都遵循。金属氧化物因其强度、稳定性和各种光学、电学和磁学性质而成为技术上重要的材料。在氧化物的制造以及它们的许多应用中，表面特性是重要的。本项目研究的材料是工业应用中使用的许多多组分系统的典型材料。因此，这种对原子结构、组成、氧化态和表面化学反应性之间关系的研究具有广泛的适用性，特别是在使用分子结构原理设计材料方面。

This is an attempt to develop a method for determining the oxidation state of surface layers of metal-oxide catalysts during a catalytic reaction. Up to now, such data have been unobtainable except under very unrealistic conditions. The method combines transient kinetics at atmospheric or near- atmospheric pressures with spectroscopy (especially Auger electron spectroscopy) under ultrahigh vacuum. Two types of oxides are studied: thick (micron-sized) films of one-and two-componement oxides on polycrystalline gold, and thin (nanometer-sized) films of spinels grown epitaxially on single crystals of gold. Raman spectroscopy and low-energy electron diffraction are used to characterize the films. Ethanol is used as a chemical probe; both acid-base and redox reactions are followed. Metal oxides are technologically important materials because of their strength, stability, and varied optical, electric, and magnetic properties. In the fabrication of oxides, as well as in many of their applications, surface properties are important. The materials studied in this project are typical of many multicomponent systems used in industrial applications. This investigation of the relationships between atomic structure, composition, oxidation state, and surface chemical reactivity therefore has wide applicability, especially for materials design using the principles of molecular architecture.