Electrochemical Promotion of Oxygen Reduction on Gold with Aluminum Phosphate Overlayer

The activities of Au electrodes with an AlPO4 overlayer were examined for oxygen-reduction reactions in alkaline media. Oxygen molecules on gold catalysts are mainly reduced by a two-electron path, forming hydrogen peroxide with half efficiency. On the AlPO4 overlayer deposited Au, larger current densities corresponding to a nearly four-electron path were recorded within the potential range of approximately 0.7−1.0 V, which were correlated with the decomposition (disproportionation) of hydrogen peroxide. This enhancement was attributed to the electronic interactions and changed activities of the intermediate state, as confirmed by X-ray photoelectron spectroscopy and the voltammetric profiles of hydrogen peroxide, respectively.