AVS 47th International Symposium
    Surface Science Monday Sessions
       Session SS1-MoA

Paper SS1-MoA2
The Role of Surface Hydrocarbon Species during Palladium-Catalyzed Reactions at High Pressures

Monday, October 2, 2000, 2:20 pm, Room 208

Session: Model Catalysts at High Pressures
Presenter: D.J. Stacchiola, University of Wisconsin, Milwaukee
Authors: D.J. Stacchiola, University of Wisconsin, Milwaukee
W.T. Tysoe, University of Wisconsin, Milwaukee
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It now appears clear that many, if not all, transition-metal-catalyzed hydrocarbon conversion reactions proceed in the presence of a relatively strongly bound carbonaceous layer adsorbed on the surface of the catalyst. In the case of Pd, ethylidyne species are present during ethylene hydrogenation, and vinylidenes in the case of reactions involving acetylene. In order to investigate adsorption on these carbonaceous-layer-covered surfaces, we have studied the adsorption of small molecules on both an ethylidyne-covered and a vinylidene-covered Pd(111) surface using molecular beam strategies and infrared spectroscopy under high pressure conditions. Results on the influence of carbonaceous layers on the hydrogenation kinetics of small hydrocarbons under high pressures are also discussed.