Berlin 2012 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 69: Competition for Gerhard Ertl Young Investigator Award

O 69.1: Vortrag

Donnerstag, 29. März 2012, 10:30–11:00, A 060

Selective Growth of Nanostructured Oxides on Au(111) as Model Catalysts — •Xingyi Deng — National Energy Technology Laboratory (NETL), United States Department of Energy, P.O. Box 10940, Pittsburgh, Pennsylvania 15236, United States — URS, P.O. Box 618, South Park, Pennsylvania 15129, United States

Metal oxides are widely used in heterogeneous catalysis as supports, promoters, additives, and catalysts, but often appear in variable phases possessing complex structural characteristics, presenting many unique challenges to elucidate mechanistic information of these catalysts. In this work, we demonstrate and highlight the use of surface-grown nanostructured oxides as model catalysts to gain fundamental insight into the reactivity of these complex systems. The key is to grow nanostructured oxides with precisely controlled composition, phase and morphology. We find that a variety of nanostructured iron-oxides (including FeO, Fe₃O₄ and α-Fe₂O₃) with well-defined morphology can be selectively grown Au(111) by carefully controlling of deposition/oxidation conditions. In addition, the polar ZnO nanostructures with a bulk-type O-ZnO(000-1) phase have been grown and discovered on the Au(111) surface which are likely stabilized via a support effect from the growth substrate. Coupling of traditional surface science techniques (STM, XPS and LEIS) with in situ capabilities at elevated pressures (AP-XPS), we have characterized these model catalysts at an atomistic detail and investigated their activity toward water and CO simultaneously. The studies of the nanostructured FeO and α-Fe₂O₃ using in situ techniques unequivocally illustrate the enhanced activities associated with the presence structural features such as edges and interfacial sites, which tend to dominate reactivity of materials in the nanocrystalline size regions.