Characterization of the microelectrode behaviour in metal electrodeposition by computation of linear potential sweep voltammetry

Abstract

Relationships between the peak current as well as the peak overpotential and the diffusion and kinetic factors depending on the electrode dimensions have been obtained on the basis of potential sweep voltammograms computed by the implicit finite difference method for metal deposition processes at disk and hemisphere electrodes. The microelectrode behaviour has been found to manifest itself not only in the deviation of peak current density and potential sweep rate relationship from linearity at low sweep rates but also in the initial increase in peak overpotential and its rapid fall with increase in the sweep rate. Independent of the kinetic parameters, the peak current takes the value of a steady-state limiting diffusion current when the sweep rate is approaching zero with the ratio of current density at disk and hemisphere equal to 4/π. The peak current density at a hemisphere electrode approaches the value at the disk electrode with increasing sweep rate.