Nature of the rest potential of platinum electrodes in alkaline alcohol solutions

Abstract

The establishment of the rest potential of the platinized platinum electrode in alakaline solution of several lower alcohols was examined. The experiments were done with a rotating wire electrode in 1 N KOH solution containing 0·5 M alcohols such as: methanol, ethanol, propanol and butanol, and a solution saturated with amyl alcohol, at 30, 40 and 60°C. The potential/time dependence of the electrode previously covered with oxygen, after addition of alcohols exhibited a characteristic. induction period. It was larger for alcohols with higher number of carbon atoms, ranging from several minutes for methanol to several hours for butanol, and shorter at higher temperatures. Without rotating, the induction period lasted only for several seconds, indicating the important effect of diffusion phenomena upon it.The phenomena observed are consistent with the assumption that the catalytic dehydrogenation of alcohols is the first step of the electrode reaction, and that the rest potential of the platinum electrode in alcohol solutions is determined by the adsorbed hydrogen.