(325f) Mechanistic Studies of the Reaction of Organosulfur Compounds on Metal Oxide Single Crystal Surfaces

The interaction of organosulfur compounds such as thiols and disulfides, with metal oxide surfaces is an increasingly important area of heterogeneous catalysis. For example, catalytic hydrodesulphurization using oxide or sulfide-based catalysts is used for the removal of sulfur from hydrocarbon feedstocks and metal oxide catalysts are used in the synthesis of thiols and alkylsulfides. While these examples illustrate the importance of the reactions of sulfur containing. compounds on oxide surfaces, the mechanisms of these reactions are generally not well understood. In an effort to develop structure-activity relationships for the reaction of organosulfur compounds on oxides we have recently started to investigate the interaction of thiols and disulfides with metal oxide single crystal surfaces. Our experimental approach is similar to that which has been used previously to study the mechanism of selective oxidation reactions on oxide surfaces and makes use of TPRS of probe molecules to measure reaction kinetics and energetics and surface sensitive spectroscopic probes such as XPS and HREELS to identify stable surface intermediates. In this talk we will present our most recent results for the reaction of methyl and ethyl thiols, sulfides, and disulfides on ZnO(0001) and TiO2(001).