Effects of energetic surface heterogeneity on ion adsorption at the electrolyte/oxide interfaces: Non-symmetrical binding-to-surface energy dispersions

The equations developed by us for the surface complexation models, taking i nto account energetic heterogeneity of surface oxygens, are applied here to study the effects of the shape of adsorption energy distribution on the io n adsorption at the oxide/electrolyte interface. The paper presents compari son of two models: one assuming that the energetical heterogeneity of oxide surface is described by a symmetrical and next a non-symmetrical adsorptio n energy dispersion for the formation of various surface complexes. The com parison of these two models was based on the obvious assumption that the va riances of both the symmetrical and the non-symmetrical distributions are e qual. The potentiometric titration data are not sensitive enough to choose the right adsorption model. So, in addition the individual isotherms of ads orption of cation and anion, of the inert electrolyte measured radiometrica lly, have been taken into consideration. The symmetrical adsorption energy distribution seems to represent the features of these adsorption systems be tter.