PHOTOELECTRON-SPECTROSCOPY (XPS) STUDIES ON SOME PALLADIUM CATALYSTS

Several Palladium chloride (PdCl2) and Palladium acetate [Pd(OAC)(2)] complexes of polymer coated silica have been developed for use as recy clable hydrogenation catalysts. The polymers used are polyacrylamides, polyvinyl pyridine, polyvinyl imidazole and copolyacrylamide methacry lic acid. These catalysts have excellent activity over several cycles of hydrogenation without any significant loss of metal or activity. Th ese catalysts were examined by XPS to identify the oxidation states of Pd acid N. The studies indicated that the more active form of the cat alyst is the one, which contained Pd(O) or a mixture of Pd (II) and Pd (O). XPS studies on nitrogen (N) showed the presence of both co-ordina ted and unco-ordinated N in the support.