Analysis of the Electrochemical Response of Surface‐confined Bidirectional Molecular Electrocatalysts in the Presence of Intermolecular Interactions

Abstract

AbstractA theoretical model for the response of bidirectional surface confined molecular electrocatalysts in the presence of intermolecular interactions is presented. Particular cases corresponding to Nernstian and fully irreversible redox behaviour are discussed, with the main features of the stationary current‐potential response being analysed in detail. This analysis has revealed important nuances in the understanding of the overall process relative to the limits of validity of some frequent assumptions, as for example, a Nernstian behaviour of the charge transfer step and therefore of the complete catalytic mechanism. The presence of interactions leads to a distortion of the current‐potential responses for which, in the case of repulsive interactions, higher overpotential values are required for a given conversion rate. In the case of non‐Nernstian charge transfer processes, high catalytic rates give rise to an increase of the overall irreversibility of the catalytic currents. The experimental verification of the model corresponding to the response of binary 11‐(ferrocenyl)undecanethiol/decanethiol in presence of ferro/ferricyanide is presented and discussed. The impact of the experimental conditions on the apparent values of the formal potential and redox rate constants of the molecular electrocatalyst is also analysed.