Synthesis, characterization and activity studies of carbon supported platinum alloy catalysts

摘要

A series of Pt-M (M = Cr, V, Zr) on carbon catalysts have been prepared using organometallic precursors. The catalysts were subjected to high temperature heat treatment to yield a supported alloy. The catalysts were characterized by XRD, ESR, chemisorption of CO, H-2, O-2, and NH3 and BET surface area. The catalysts were evaluated for vapor phase hydrogenation of phenol and benzene. The thioresistance level of these alloy catalysts was studied for benzene hydrogenation reaction. Alloy formation was confirmed by X-ray diffraction analysis. The characterization shows that the catalysts used here were alloys, with some platinum exposed, covered by MO, (M = Cr, V,Zr) species. The addition of the second metal suppresses chemisorption, but that oxygen and ammonia adsorption increased with the addition of the second metal. It was also observed that hydrogenation activity is increased when compared with Pt/C catalyst. The catalysts were highly selective either for cyclohexanone or cyclohexanol in phenol hydrogenation reaction. The alloy catalysts exhibited high thiotolerance level when compared to a Pt/C catalyst. (C) 1998 Academic Press [References: 85]