The redox reaction of hydrogen peroxide at an Au(100) electrode: Implications for oxygen reduction kinetics

The redox reaction of hydrogen peroxide (O-2 + 2H(+) + 2e reversible arrow H2O2) at an Au(100) electrode/0.1 M HClO4 interface and the kinetic H-D isotope effect for O-2 reduction have been investigated. It was found that i) the kinetics for electrochemical oxidation of H2O2 to O-2 are very fast, occurring at a potential very close to its equilibrium potential (E-O2/H2O2(eq)); ii) the kinetics for O-2 reduction to H2O2 are much slower than those for H2O2 oxidation, with a H-D kinetic isotope effect of above two; and iii) the onset overpotential of H2O2 + 2H(+) + 2e -> 2H(2)O is ca. 1.4 V. Mechanistic insight and the origin for the high overpotential at the onset for O-2 reduction at Au(100) are discussed. (C) 2013 Elsevier B.V. All rights reserved.