The importance of adsorption in anodic surface‐catalyzed oxygen‐transfer reactions at gold electrodes

Abstract

Abstract A large number of anodic oxygen‐transfer reactions were studied at Au electrodes in both acidic and alkaline media. Results of competitive adsorption studies are interpreted and support the conclusion that adsorption is a prerequisite to subsequent oxygen‐ and electron‐transfer steps. Many of these oxidation reactions gave the voltammetric appearance of reversible waves, even though the observed half‐wave potential values were shifted hundreds of millivolts positive of the thermodynamic potentials. A catalytic mechanism is proposed in which adsorbed hydroxyl radicals (AuOH) participate in the oxygen‐transfer step. The absence of pH effects on half‐wave potentials for several inorganic compounds suggests that the electron transfer precedes the deprotonation step for these reactants.