LINEAR-SWEEP VOLTAMMETRY OF IRREVERSIBLE ELECTRON-TRANSFER IN SURFACE-CONFINED SPECIES USING THE MARCUS THEORY

A theoretical analysis suggests a relationship between an observed rea ction rate constant and a differential rate constant, which is related to the Marcus theory of electron transfer. Consequently, assumptions from the Marcus theory are used to derive an expression for the curren t as a function of overpotential during linear-sweep voltammetry in th e case of kinetically irreversible electron transfer between an electr ode and a surface-confined redox species. A method for the extraction of kinetic parameters from experimental current vs potential data is a lso described. The application of this procedure is demonstrated in th e electron transfer between gold electrodes and strongly adsorbed cyto chrome c through a self-assembled alkanethiolate monolayer.