COLL 483 |
| Bruce E. Koel, Department of Chemistry, Department of Chemistry, University of Southern California, SSC 606, 920 W 37th St, Los Angeles, CA 90089-0482 |
| Local surface structure and composition plays an important role in governing electrochemical reactions. In order to provide benchmarks for theoretical calculations and simple model systems relevant to elementary processes at electrochemical interfaces, STM was used in UHV to image surfaces of several Sn/Pt(111) and Sn/Pt(100) ordered surface alloys in order to obtain real-space, atomistic level information about the composition, structure, local-ordering, defects, and domain boundaries present. Both chemical contrast between Pt and Sn, and“electronic contrast”, i.e., that it is possible to discriminate between Pt atoms in different local environments with the STM, were demonstrated. Also, STM was used to study the SnOx film that is formed by oxidation of these alloys and also its thermal stability, including the several ordered surface phases that can be formed depending on the annealing temperature. Conditions are described for the formation of self-organized, molecular-sized, hexagonally ordered SnOx nanodot superlattices on Pt(111), and the growth of large-scale, oriented single crystals of SnO2 on reduced SnOx wetting layers on Pt(111). |
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Electrochemistry and Surface Science Symposium in Memory of Mike Weaver
Division of Colloid and Surface Chemistry |