Specific Adsorption in the Stern Layer

Abstract

In this chapter we shall continue the analysis of the above system of equations (81), (82) for the double layer electrostatic potentials (see Chapter II) and show that in the presence of specific adsorption forces this system leads to the Stern isotherm (in the preceding chapter we demonstrated that in the absence of these forces the systems leads to the Gouy-Chapman and Wagner-Onsager-Samaras equations). Thus, using system (81), (82), one can construct a unified theory of the ionic part of EDL, which not only includes the classical theories as a particular case, but permits their substantial generalization and improvement. For instance, in the presence of specific adsorption an equation follows from (81), (82), which gives the potential of the plane of maximum approach and its dependence on various parameters, such as electrolyte concentration, electrode charge, etc. This enables the law of the shift of the zero-charge points to be established for the electrode, the Stern layer, and the Gouy layer (all these points appear to be different) and the law of the shift of the capacity minimum to be calculated (its position coincides, in general, with none of the three zero-charge points).