Sulfur Resistance of PtPd Catalysts : Preparation, Characterization and Catalytic Testing

摘要

Pt, Pd and PtPd metallic precursors are deposited on amorphous silica aluminas anddealuminated FAU zeolites. The catalytic activity is measured in the hydrogenation of toluenein the absence or presence of sulfur (200 ppm). In the absence of sulfur, alloying Pt with Pddecreases the hydrogenation activity. In general, catalysts made from ammoniated precursorsare the most active with one remarkable exception. In the presence of sulfur, thioresistance isa function of reaction temperature, i.e. sulfur coverage of the metallic phase. Pd increasessubstantially the sulfur resistance. The effect of support acidity on thioresistance is observedonly at high sulfur coverage.