Impedance investigations of the mechanism of oxygen evolution on compositeelectrodes

Impedance measurements of the oxygen evolution reaction on a composite elec trode prepared from an ethylene-propylene terpolymer (EPDM) admired with ac etylene carbon black have been carried out. A theoretical analysis of measu red impedance is presented. The mechanism of the oxygen evolution reaction has been determined. The oxygen evolution reaction is composed of two elect rochemical steps and one chemical step. The slowest step for the oxygen evo lution reaction is the first charge transfer step which is based on the for mation of an intermediate OHAd adsorbed species. (C) 1999 The Electrochemic al Society. S0013-4651(98)03-112-7. All rights reserved.