Adsorption studies of gases on Pt-Rh bimetallic catalysts by reversed-flowgas chromatography

In the present work, the relatively new technique of reversed-now gas chrom atography was applied for the study of adsorption of carbon monoxide, oxyge n, and carbon dioxide on Pt-Rh bimetallic catalysts. Using suitable mathema tical analysis, equations were derived by means of which rate constants for adsorption, desorption; and disproportionation reaction were calculated. F rom the variation of these rate constants with temperature and the nature o f the catalyst (Pt content), as well as from the finding that the CO adsorp tion is a dissociative process, useful conclusions concerning the mechanism for the CO oxidation reaction over Pt-Rh bimetallic catalysts were extract ed. The catalytic fractional conversions for the CO disproportionation reac tion were found to be higher for the Pt-Rh bimetallic catalysts than those for the pure Pt catalyst, indicating the presence of beneficial Pt-Ph syner gism.