Nanoceria-Modified Platinum-Gold Composite Electrodes for the Electrochemical Oxidation of Methanol and Ethanol in Acidic Media

Nanocrystalline Pt/Au/CeO2 composite electrodes of varying Pt/Au ratios were prepared oil polycrystalline Pt and Au electrodes by simultaneous electrodeposition from K2PtCl6, AuCl3, and CeO2 solutions. The ratio of Pt:Au was varied from 0:2 to 2:0. It was observed that the electrodes prepared from a 2:1 Pt:Au Solution yielded a slightly higher Current for the oxidation of methanol. Scanning electron microscopy showed stark changes in the electrode morphology and Surface area as the Au concentration is increased. The morphology of the electrodes varies with the ratio of PI:Au, ranging from a relatively smooth deposit for Pt, a globular particulate for Pt:Au, and a dendrite-like triangular shape For Au. It was also observed that the 1:2 Pt:Au ratio gave a 2-fold increase in the oxidation Current for the oxidation of ethanol, suggesting that the Pt:Au composite electrode proves to be a better catalyst for the electrochemical oxidation of ethanol. The changes in morphology of the film call probably be attributed to the catalytic enhancement ill ethanol. However, the increase in the Current is larger than what can be explained by Surface area effects, Suggesting a synergistic effect for the electrochemical oxidation of the alcohol.