Study of the methanol oxidation reaction on platinum using the potential-step technique

Abstract

Anodic potential steps were applied to a smooth platinum electrode in pure and methanolic sulphuric acid solutions. Rising current against time transients were observed in the potential range 0.6–0.8 V against the normal hydrogen electrode (NHE), corresponding to the methanol oxidation reaction. The bifunctional role of platinum electrocatalysts, encouraging the simultaneous adsorption of water and methanol, is clearly demonstrated. The rising current against time data are fitted to a mathematical model previously proposed for a nucleation and growth process in which the current is controlled by charge transfer and diffusion processes before being finally limited by an increasing oxide film.