Mechanistic approach to the oxidation of phenol at a platinum/gold electrode in an acid medium

The electrochemical oxidation of phenol was investigated at a platinum/gold (60/40 at.%) alloy electrode in a 0.5 M H2SO4 aqueous solution at 308.7 K by cyclic voltammetry. Comparative studies were carried out by using platinum and gold electrodes under similar experimental conditions. A tentative mechanism on the electrochemical oxidation of phenol at Pt, Au and Pt/Au electrodes is proposed. It is based on the incipient hydrous oxide adatom mediator model of electrocatalysis and generalizes the behaviour of all electrodes studied in the oxidation of phenol. The advantage of the alloy catalyst is due to the more effective removal of the surface fouling which is attributed to the presence of an alpha(2)-phase. (C) 1998 Elsevier Science S.A.