Surface Catalytic Mechanism in Square-Wave Voltammetry

Abstract

A pseudo-first-order catalytic mechanism in which both reactant and product of the redox reaction are strongly immobilized on the electrode surface is theoretically analyzed under conditions of square-wave voltammetry (SWV). A mathematical procedure is developed for diffusionless conditions. The relationships between the properties of the voltammetric response and both the kinetic parameters of the redox reaction and the parameters of the excitement signal are studied. The phenomenon of the quasireversible maximum is discussed. The theoretical results are confirmed with the experiments of azobenzene performed in a presence of hydrogen peroxide. In acetate buffer with pH 4.2 the standard rate constant of charge transfer of azobenzene is ks = 12 s−1 and the catalytic rate constant in the presence of hydrogen peroxide is kc = 2.24×104 s−1 mol−1 L.