PROPENE HYDROGENATION WITH PT-AG INTERMETALLIC PHASES SUPPORTED ON SIO2 GELS

Various intermetallic phases composed of Pt/Ag supported on SiO2-gel were synthesized by reduction of Pt(allyl)2 and Ag[cyclooctadiene]2+ precursors anchored on the support surface. This method afforded highly dispersed metallic particles. X-ray analysis was used to ascertain the occurrence of alloy, for structural identification of Pt/Ag phases and degree of dispersion. The catalytic activity of these systems was studied in gas-phase hydrogenation of propene within the temperature range 10-90-degrees-C. Kinetic parameters such as specific reaction rates, reaction orders and apparent activation energies were calculated as functions of the Pt/Ag ratio. Results are compared and discussed in terms of the structural and electronic features of the active metallic phase.