Aqueous and Surface Redox Potentials from Self-Consistently Determined Gibbs Energies

A self-consistent band theory has been developed for electrochemical interfaces. The surface potential is adjustable by adding surface charge, and a counter charge distribution in the double layer is determined self-consistently using a modified Poisson−Boltzmann theory within a dielectric continuum model. We demonstrate a theory to predict, to useful accuracy, the reversible potentials for 34 acid or base aqueous phase reactions and 4 reactions that are key to understanding electrocatalysis by platinum in oxygen cathodes in fuel cells. We believe this theory will find many applications.