METHANOL OXIDATION ON PLATINUM-TIN CATALYSTS DISPERSED ON POLY(3-METHYL)THIOPHENE CONDUCTING POLYMER

Platinum-tin catalysts were prepared by electrodeposition on poly(3-methyl)thiophene to investigate the effect of catalyst support and Pt loading on the electrochemical oxidation of methanol. The polymer-catalyst assembly was characterized by SEM/EDX, surface area measurements, and Rutherford backscattering spectrometry (RBS). The Pt-Sn catalyst deposited in the hydrogen adsorption potential region showed an order of magnitude higher surface area. RBS studies enabled the estimation of the thickness and the distribution of the catalyst layer in the conducting polymer support. Methanol oxidation currents were negligible at catalyst loadings less than 60-mu-g/cm2, but hydrogen oxidation was observed at Pt loadings as low as 20-mu-g/cm2.