Electrochemical fabrication of Pt-Au-WO3 electrodes for direct methanol fuel cell.

Pt-Au-WO3 ternary electrodes with various compositions were synthesized by electrochemical method from a mixture of H2PtCl6 aqueous solution, HAuCl4 aqueous solution, and W-peroxo complex. Their electrocatalytic activities for methanol oxidation were investigated. Film composition was controlled by varying the concentration of each component in electrolytes. Morphology and compositional analyses of the synthesized films were performed by scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). The catalytic activity and initial behavior of current density for methanol oxidation of the synthesized films were measured using cyclic voltammetry (CV) and chronoamperometry (CA) in a mixture of 0.5 M H2SO4 and 0.5 M CH3OH solution. Electrocatalytic activity for CO oxidation was also evaluated in 0.5 M H2SO4 solution. The activities of various electrodes for methanol oxidation were found to be strongly dependent on film composition. Pt-Au-WO3 electrodes exhibited higher activity for CO oxidation than pure Pt. The addition of proper amount of Au and WO3 significantly improved catalytic activity for methanol oxidation.