Stripping voltammetry and chronoamperometry of an adsorbed species with repulsive lateral interactions

In this paper a simple model is considered for the stripping voltammetry and chronoamperometry of an adsorbed species with repulsive lateral interactions. In the limit of strongly repulsive lateral interactions, the chronoamperometric transient is predicted to be hyperbolic, i.e. to have a t-1 dependence. This dependence is confirmed by both the numerical simulation of the mean-field equations and by the Dynamic Monte Carlo simulations. However, in the analysis of the Dynamic Monte Carlo simulations, inflexion points are found in a log-log plot of the data, corresponding to the formation of ordered configurations on the surface. The stripping voltammetry exhibits broader stripping peaks with increasingly repulsive lateral interactions. An analysis of the peak potential versus the logarithm of the scan rate yields the Tafel slope, irrespective of the strength of the lateral interactions. In the Dynamic Monte Carlo simulations, strong repulsive interactions lead to multiple stripping peaks, the peaks becoming more pronounced with a faster surface diffusion of the adsorbed species. These peaks are related to the existence of ordered configurations on the electrode, whose long-range order is enhanced at faster diffusion rates.