Thermodynamic considerations of the various contributions to overpotential. Part 1

Abstract

A relation among overpotential, current density and entropy production in local from is derived. The above relation is employed in order to define charge-transfer, reaction and diffusion overpotential in a rigorous way. On the basis of the definition of charge-transfer overpotential the Tafel equation is derived without having recourse to the formal separation of the standard-free energy change relating to the electrode process into a potential-dependent and a potential independent part.