Mean field approach applied to surface deposition on a modified electrode

PASINETTI, PEDRO MARCELO; PAZ ZANINI, VERONICA I.; RAMIREZ-PASTOR, ANTONIO; PINTO, OSCAR ALEJANDRO

PHYSICAL CHEMISTRY CHEMICAL PHYSICS

ROYAL SOC CHEMISTRY

Año: 2021

1463-9076

In this work we study the deposition phenomena on a modified electrode in the framework of the mean field theory. The electrode surface is modified by the irreversible deposition of impurities which can block a fraction of the adsorption sites. Then, an electroactive species is allowed to adsorb on the accessible sites, transferring electric charge and generating a current that can be calculated and measured. Nearest-neighbor lateral interactions are considered both between electroactive particles and between particles and impurities. The modified Bragg-Williams theoretical approach considers both the blocking effects of impurities and the lateral interactions, through the different concentrations of impurities and particles. The analysis is based on the study of adsorption isotherms and voltammograms, considering different interaction energies and impurities concentration. The potentialities and limitations of the analytical approximation are discussed by comparing theoretical predictions with Monte Carlo simulation and experimental measurements in which an artificial clay represents the impurity and a [Fe(CN)6]4 redox probe is the species that transfers the charge.