The partial discharge of electrosorbates and its influence in electrocatalysis

Abstract

The integral charge flow during electrosorption processes can be described by the electrosorption valency, γ. This dimensionless thermodynamic parameter consists of contributions from the penetration of the substance into the double layer, g, and the partial charge transfer, λ. g varies between 1 for discharged substances and very small values, gmin, for electrostatic adsorption without transfer. The charge transfer coefficient, λ, can be estimated empirically using Pauling's concept of electronegativity, χ, but the quantitative correlation is different for anions and cations due to the different type of bonding. The γ value of special electrosorbates depends on the nature of the solvent and ligands. Theoretical model calculations justify the influence of χ and solvation. The partial discharge of ions causes a decreasing electrostatic influence in electrocatalysis. Examples are given for ion (ITR) and electron transfer reactions (ETR). Keywords: electrosorption valency, partial charge transfer, bond formation, solvation, double layer.