Coelectrodeposited Pt/WO3 electrodes have very high activity for the oxidation of methanol and formic acid. However, WO3 has a slight solubility at 60 degrees C in sulfuric acid media and this significantly reduces its activity and stability. By covering such an electrode with a thin layer of Nafion dispersion, the solubility of WO3 is reduced significantly, electrode performance is stable, and electrode activity is not affected.