Electrocatalysis under Temkin adsorption conditions

Abstract

The theoretical description of steady-state current–potential curves for simple electrocatalytic reactions under Temkin adsorption conditions has been extended beyond the potential range of quasi-equilibrium. The theory predicts that current–potential curves calculated on the basis of Langmuir and Temkin adsorption conditions exhibit only minor differences at coverages below 0.9. The volcano curve for hydrogen evolution by the Volmer–Heyrovsky reaction mechanism proves to be independent of the nature of the adsorption isotherm if plotted against the apparent free energy of adsorption at equilibrium coverage under standard conditions. For any other value of the free energy of adsorption, however, the width of the volcano curve depends on the Temkin heterogeneity factor f. The volcano curve is not truncated under Temkin adsorption conditions.