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.

Boosting water oxidation layer-by-layer

“…Additionally, these lateral repulsive interactions can also dictate the shape of the oxidation peaks and may be a contributory factor to the broadening of the Ir(IV)/Ir(V) peak. Several other factors may also lead to the observed peak broadening including a distribution of formal potentials in the LbL film 49 or coupled ion-electron transfer processes. 50 Finally, as the potential applied is increased beyond 0.95 V, the surface coverage of Ir(V) increases to the extent that the conditions for the formation of O-O are reached and molecular oxygen (O 2 ) is released as a product of the electrocatalytic reaction.…”

Study of charge transfer processes in a surface confined redox system by means of differential staircase voltacoulommetry

“…This meant using very short time pulses, thus transforming the response to quasi-reversible, which is much more complicated to analyse [4][5][6][7][8], and which could present a notorious distortion, due to non-faradaic effects [10]. That may be the reason for which these methods have not been so widely used as cyclic voltammetry (CV), a technique which presents simple theoretical criteria for the analysis of these systems but which also presents problems in the experimental evaluation of electroactive monolayers, mainly due to the complex double layer influences associated to the I-E response [11][12][13].…”

Kinetic characterization of Prussian Blue-modified graphite electrodes for amperometric detection of hydrogen peroxide

“…The discrepancies can be attributed to the attractive interactions between the adsorbed redox centers [14]. Moreover, as expected in the case of lateral interactions [16], the peak parameters were slightly affected by the surface coverage.…”