Electrochemical Oxidation of Methanol and Ethanol at Rh@Pt and Ru@Pt Catalysts

Abstract

The influence of the amount of Pt deposited onto Rh and Ru nanoparticles on the oxidation of methanol and ethanol has been compared in H2SO4(aq) at ambient temperature and in a proton exchange membrane (PEM) cell at 80 °C. In H2SO4(aq), Rh@Pt and Ru@Pt show similar enhancements in activities over Pt for both methanol and ethanol oxidation. However, differences in the optimum Pt coverage indicate that compression of the Pt lattice by Rh plays a dominate role, while ligand effects are more important for Ru@Pt. In the PEM cell, the Ru core enhanced activities significantly for both methanol and ethanol, while activities were suppressed by the Rh core. This may arise from dominance of ligand and/or bifunctional effects for the Ru@Pt catalyst at 80 °C. Data from the PEM cell showed that the stoichiometry for ethanol oxidation at Ru@Pt was higher than for Rh@Pt, indicating a higher selectivity for the complete oxidation to CO2.