Cyclic voltammetric studies of alumina supported monometallic Pt and bimetallic Pt and unknown;Sn catalysts using carbon paste electrodes

Abstract

The present work relates to the cyclic voltammetric studies of alumina supported monometallic Pt and bimetallic Pt---Sn catalysts using solid carbon paste electrodes. The cyclic voltammetric data of the solid catalysts, which were reproducible, were in agreement with those of electro-deposited Pt and Pt---Sn electrode systems. The reversibility of the H-adsorption–desorption system in representative 0.3 Pt–Al₂O₃ monometallic catalyst was confirmed by the difference between the anodic and cathodic peak potentials. The unit ratio of the cathodic to anodic peak currents observed, indicated the equality of the transfer coefficient in the kinetics for the respective processes. The O₂-adsorption–desorption reaction was found to be irreversible as expected. The lower area of the curve for H-adsorption–desorption in the case of bimetallic catalysts gives an indication for the formation of alloys. The use of a carbon paste electrode in studying the cyclic voltammetric behavior of heterogenous catalysts yielded qualitative information about the activity of the catalysts. Good correlations were found between cyclic voltammetric parameters and activity results in both monometallic and bimetallic catalysts.