Characterization of Catalyst Particles in Reactive Atmospheres

本研究的目的是确定氧化物载体或碳上的混合金属催化剂体系的微观结构如何以无法从单个组分的性质预测的方式影响反应性和选择性，并利用微观结构的变化来控制负载催化剂的性质。目前正在研究三种类型的体系：含有贵金属和卤素、碱金属、稀土、贱金属和/或另一种贵金属的多组分粒子；各种氧化物载体上的贱金属催化剂；还有碳原子上的粒子。高分辨率透射电子显微镜用于表征多组分粒子组分之间的相互作用以及粒子与载体的相互作用。研究了石墨、非晶碳和炭黑上的颗粒，以确定不同类型的碳载体和处理对结构和催化性能的影响。多组分系统的微观粒子表征技术通过使用高分辨率分析透射电子显微镜和扫描隧道显微镜得到了扩展。这是研究人员实验室正在进行的努力的延伸。所研究的系统是根据它们与工业过程或环境控制中实际使用的催化剂的相关性而选择的。

The objectives of this research are to determine how the microstructure of a mixed metal catalyst system on an oxide support or on carbon influences reactivity and selectivity in ways not predictable from the properties of the individual components, and to use variation in microstructure to control the properties of supported catalysts. Three types of systems are under study: multicomponent particles containing a noble metal and halogen, alkali metal, rare earth, base metal and/or another noble metal; base metal catalysts on various oxide supports; and particles on carbon. High- resolution transmission electron microscopy is used to characterize interactions between constituents of multicomponent particles as well as interactions of particles with supports. Particles on graphite, amorphous carbon, and carbon black are studied to determine how different types of carbon supports and treatment affect structures and catalytic properties. Microscopic particle characterization techniques for multicomponent systems are expanded by using high- resolution analytical transmission electron microscopy and scanning tunnelling microscopy. This is an extension of ongoing efforts in the laboratory of the investigators. The systems studied are selected for their relevance to catalysts actually used in industrial processes or in environmental control.