MODELING OF THE DOUBLE-LAYER AND ELECTROSORPTION OF A PATCHWISE HETEROGENEOUS SURFACE ON THE BASIS OF ITS HOMOGENEOUS ANALOG .1. NONINTERACTING PATCHES

A model for the description of the influence of patchwise surface hete rogeneity on the double layer structure and proton electrosorption is developed on the basis of the perturbation method using the Henry-Deby e-Huckel approximation. Lateral screening between patches is neglected (non-interacting patches). Equations are obtained which characterize the electrodesorption of protons and express the potential and charge averaged over a heterogeneous surface as a function of the charge and potential of an analogous homogeneous surface, a heterogeneity paramet er, the pH and the Debye length. Under the accepted retrictions on the generality of the treatment, i.e. low potentials (low charge densitie s), monocomponent adsorption and constant sign of patch charges, patch wise heterogeneity exerts a surprisingly weak influence on double laye r structure and adsorption.