Research Initiation Award: Novel Supported Molybdenum and Tungsten Sulfide Catalysts

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This project deals with supported molybdenum sulfide, cobalt- promoted molybdenum sulfide, and tungsten sulfide catalysts prepared by the decomposition of the respective thiosalts in hydrogen or helium. The activities of such catalysts, as determined by suitable test reactions, are compared with those of catalysts having the same metal content but prepared by conventional methods. The effects of various pretreatments on total area, oxygen chemisorption, and activity are investigated. Pretreatments include the removal of excess sulfur by temperature-programmed reduction or by reductive sulfiding. Correlations between oxygen chemisorption and catalyst activity are obtained for various sulfur contents as well as for catalysts prepared in each of the atmospheres (hydrogen or helium) for decomposition of the thiosalts. Supported sulfide catalysts play a vital role in coal liquefaction and in the petrochemical industry. Active sulfide catalysts are conventionally prepared by converting the respective oxides to sulfides, but this is often difficult and does not proceed in a regular manner. This work explores the utility of catalysts prepared by a different technique that may yield more uniform and more active catalysts.