CALCULATION OF CYCLIC VOLTAMMETRIC RESPONSES FOR THE REDUCTIVE FORMATION OF CATALYST-SUBSTRATE ADDUCTS ON ELECTRODE SURFACES

Electrocatalysts based on monolayers of transition-metal complexes att ached to electrode surfaces frequently follow mechanisms in which a ch emical step is interposed between the first and subsequent electron-tr ansfer steps. The cyclic voltammetric responses to be anticipated for such systems were calculated using finite difference procedures to sol ve the relevant differential equation. The calculated variation of the peak currents and peak potentials with the kinetic parameters governi ng the three steps in the mechanistic scheme are presented in graphica l form. Application of the results to a specific experimental system, the catalysis of the electroreduction of O-2 by a macrocyclic complex of Co-III adsorbed on graphite electrodes, produced reasonable agreeme nt between calculated and observed cyclic voltammograms.