Electroreduction kinetics of the peroxodisulfate anions oil the electrochemically polished Bi(111) single crystal electrode has been studied by impedance spectroscopy. Influence of the electrode potential, reaction intermediates, base electrolyte and reactant concentrations on the kinetic parameters of electroreduction has been established. Systematic analysis of the fitting results demonstrates the noticeable influence of adsorption of the reaction intermediate or reactant on the electroreduction rate of the S2O82- anions at the Bi(111) electrode. In the region of so-called "current pits" in the cyclic voltammetry Curves, obtained by rotating disc electrode method, the mixed kinetics, i.e. the adsorption and "true" charge transfer limited steps have been established by impedance spectroscopy. (C) 2007 Elsevier Ltd. All rights reserved.