Voltammetry of Adsorbed Molecules. Part 1: Reversible Redox Systems

Abstract

When strongly adsorbed or chemisorbed molecules behave “ideally” it is a relatively simple process to interpret linear sweep voltammograms and extract thermodynamic and kinetic information. Unfortunately it is rare that the criteria for ideality are met and other models have to be developed from which to extract information about the adsorbed redox system of interest. In the last 15–20 years models have been developed which allow for the influence of such factors as lateral interactions, adsorbed dipoles, a distribution of formal potentials, multiple redox sites, interfacial potential distribution, ion pairing, and acid-base equilibria. These models are reviewed with an emphasis on the underlying assumptions on which the each model was derived. Diagnostic criteria are provided from which it may be determined which of the above phenomena, if any, are effecting the voltammetric response.