Synthesis and characterization of Pt-WO₃ as methanol oxidation catalysts for fuel cells

Several compositions of Pt-WO₃ catalysts were synthesized and characterized for the electro-oxidation of methanol and CO. The surface morphologies of the catalysts were found to be dependent on the composition. X-ray energy dispersive spectroscopy and X-ray photoelectron spectroscopy results suggest a surface enrichment of WO₃ in the codeposited Pt-WO₃ catalysts. Cyclic voltammetry and chronoamperometry in methanol show an improvement in catalytic activity for the Pt-WO₃ catalysts. A significant improvement in the poison tolerance toward CO and other organic intermediates was observed in the mixed metal-metal oxide catalyst. The catalytic performance of the different compositons was directly compared by normalization of the current to active sites. CO-stripping voltammetry suggests the involvement of WO₃ in the catalytic process as opposed to a mere physical effect as suggested by previous work. A possible mechanism for this improvement is proposed based on the electrochemical data.