Ethylene hydrogenation on Pt thin films on Ni(100) surface

From XPS and LEED studies, a layer-by-layer growth of Pt thin films is indicated up to 8 ML coverage on Ni(1 0 0) surface while a (1 x 1) structure changes to a disordered structure above 2 ML of Pt film thickness. The 1 ML Pt overlayer, as a model (1 0 0) surface of Pt-Ni alloy single crystal, shows a considerable d-band narrowing probably due to the formation of an interface state with the Ni substrate. This induces weakly adsorbed hydrogen atoms and ethylene molecules and, as a result, the maximum evolution of ethane is observed around 200 K. A wide d-band extending to -6 eV binding energy is developed for Pt 6 ML film characteristic of bulk Pt electronic states, resulting in a similar surface chemistry of ethylene as on Pt(1 1 1) surface. (C) 2001 Elsevier Science B.V. All rights reserved.