Atomic Level Control and Probing of Chemical Reactions at Surfaces

在分析和表面化学计划和多学科活动办公室的支持下，本研究项目对双金属表面的结构和反应性进行了原子水平的研究。南加州大学的Koel教授和他的同事开发了一种超高真空扫描隧道显微镜仪器，它可以识别金属表面的吸附位置和分子吸附。模型双金属表面的反应性与原子能级结构以及这些表面上台阶和缺陷位置的占有率之间的关系将被建立。铂锡合金表面和难熔金属衬底上的钯薄膜正在被研究，这些表面上的各种碳氢反应，包括乙炔三聚生成苯，正在被探索。从这些研究中获得的见解将有助于加深我们对重要催化过程的理解。在这项研究项目中，双金属表面的原子能级结构与这些表面的反应化学性质之间存在着关联。考察了与多相催化相关的碳氢反应在表征良好的铂-锡和钯-钼衬底上的变化，以探讨金属原子团簇和缺陷位在这些表面上的影响。使用扫描探针显微镜的原子水平表征构成了这些研究的基础，这将为重要催化系统的运行提供洞察。

Atomic level studies of structure and reactivity of bimetallic surfaces are carried out in this research project supported by the Analytical and Surface Chemistry Program and the Office of Multidisciplinary Activities. Professor Koel and his coworkers at the University of Southern California have developed ultra high vacuum scanning tunneling microscope instrumentation which allows the identification of adsorption sites and molecular adsorbates on metallic surfaces. Correlations between reactivity of model bimetallic surfaces and the atomic level structure and occupation of step and defect sites on these surfaces will be made. Pt-Sn alloy surfaces, and Pd thin films on refractory metal substrates are being examined, and various hydrocarbon reactions on these surfaces, including acetylene trimerization to form benzene, are being probed. Insights gained from these studies will be valuable in developing our understanding of important catalytic processes. Correlations between atomic level structure of bimetallic surfaces and the reaction chemistry of these surfaces are being made in this research project. Hydrocarbon reactions relevant to heterogeneous catalysis are examined on well characterized Pt-Sn and Pd-Mo substrates, in order to probe the effect of metal atom ensembles and defect sites on these surfaces. Atomic level characterization using scanning probe microscopy forms the basis of these studies which will provide insight into the operation of important catalytic systems.