The Resolution of the Volmer-Heyrovsky-Tafel Mechanism with a Normal Distribution of the Standart Gibbs Energy of Adsorption

Abstract

On the basis of a generalized model for hydrogen adsorption recently proposed by the authors, a heterogeneous electrode surface was simulated through a normal distribution function of the standard Gibbs energy of adsorption. The Volmer-Heyrovsky-Tafel mechanism for the hydrogen evolution reaction was then evaluated under steady state conditions without any kinetic approximation. The dependence of the surface coverage and the current density on the overpotential was analyzed for each route. It was concluded that surface heterogeneity produces substantial modifications in the previously known kinetic behavior of the Volmer-Heyrovsky-Tafel mechanism.