Theory of reverse scan square-wave voltammetry influenced by the kinetics of reactant adsorption

A model of electrode reaction complicated by slow adsorption of the reactant is developed for square-wave voltammetry with inverse scan direction. The relationship between the dimensionless net peak current and the logarithm of dimensionless rate constant of adsorption is a curve with a minimum and a maximum. For this reason the ratio of real net peak current and the square-root of frequency is a non-linear function of the logarithm of frequency and exhibits either a maximum or a minimum. The frequency of extreme serves for the estimation of the rate constant: log(k _ads /D ^1/2 ) = log(k* _ads )_crit + 0.5 log f _crit , where (k* _ads ) _crit is a critical dimensionless rate constant of adsorption. Square-wave voltammetry is sensitive to the kinetics of adsorption if k _ads < 10² cm s⁻¹