Methanol electrooxidation at Pt-Ru-W sputter deposited on Au substrate

This work reports an improved electrocatalytic activity for methanol oxidation at Pt-Ru-W electrode sputter deposited on Au substrate. The performance of Pt-Ru-W was compared with that of Pt-W and of Pt-Ru alloy electrodes. All the alloys tested exhibited catalytic activity higher than Pt. Among the alloys tested, the Pt-Ru-W demonstrated a significant cathodic shift in the onset potential and a remarkable enhancement in the current density for methanol oxidation reaction (MOR). The onset potentials for the MOR matched well the anodic peak potentials recoded in the base electrolyte (H2SO4), i.e., 0.15 V versus Ag/AgCl for Pt-Ru-W and 0.35 V versus Ag/AgCl for Pt-W and Pt-Ru electrodes. From these findings, it was postulated that the background peak current generates oxide species necessary to complete the methanol oxidation to CO2. Next, it was observed that the current density at Pt-Ru-W electrode decreased when the An substrate was changed to Pt, C, or Si, although, the onset potential for MOR remained almost unaffected by the nature of the substrate. Afterwards, the effect of Au substrate on methanol oxidation at Au-based alloy electrodes was investigated. (C) 2004 Elsevier B.V. All rights reserved.