ELECTROCHEMICAL OXIDATION OF HYDROGEN-PEROXIDE AT PLATINUM-ELECTRODES- PART 1 - AN ADSORPTION-CONTROLLED MECHANISM

The electrochemical oxidation of H2O2 at a platinum rotating disk elec trode was studied at pH 7.26 for the [H2O2] range 0-80 mM and for rota tion rates 630-10,000 r.p.m. A mechanism is proposed to account for th e steady-state current response as a function of both relation rate an d [H2O2]. The mechanism incorporates reversible binding of hydrogen pe roxide to electrochemically generated Pt(II) surface sites with inhibi ting competitive adsorption of dioxygen at these sites. A further inhi biting side reaction is also identified involving protonation of the s urface adsorbed H2O2 complex. (C) 1997 Elsevier Science Ltd.