Rate constants of adsorption reactions from voltammetric current-potential curves or galvanostatic potential-time curves on heterogeneous surfaces

Abstract

For the anodic removal of adsorbed hydrogen atoms by the triangular sweep method or by charging curves, the rate constants of the Volmer reaction may be determined with the aid of theoretical curves computed numerically by a digital computer. The heterogeneity of the surface is represented by two overlapping regions with Langmuirian behaviour. The charging of the double layer is taken into account for both methods, and the effect of the ohmic potential drop between test electrode and the tip of the Luggin capillary of the reference electrode is considered in the voltammetric measurements. The concept of the pseudocapacitance for galvanostatic charging under non-equilibrium conditions is discussed critically.