EFFECT OF THE INTERFACIAL POTENTIAL DISTRIBUTION ON THE MEASUREMENT OF THE RATE-CONSTANT FOR ELECTRON-TRANSFER BETWEEN ELECTRODES AND REDOXADSORBATES

The effects of the interfacial potential distribution on cyclic voltam metry of adsorbed redox molecules exhibiting slow (quasi-reversible an d irreversible) electron transfer is considered in a theoretical model . Results of numerical simulations based on this model are presented a nd compared to cyclic voltammograms and measurements in the absence of double layer effects. The slopes of plots of peak potential versus lo g sweep rate are the same, i.e., RT/alpha nF and RT/(1 - alpha)nF for the cathodic and anodic reactions, respectively, as predicted in the a bsence of double-layer effects. The calculation of the rate constant c an be greatly influenced by the double-layer effects.