Interfacial dipole moment induced by contact adsorption

2 Interfacial dipole moment induced by contact adsorption 

In the course of ionic contact adsorption on the interface of metal electrode, hydrated ions are first dehydrated and then adsorbed at the inner Helmholtz plane in the compact layer as shown in Fig. 5-27 and as described in Sec. 5.6.1. In the interfacial double layer containing adsorbed ions, the combined charge of motal and adsorbed ions = z eF on the metal side is balanced with the 

Contact ion adsorption on metal electrodes in aqueous solution IHP = inner Helmholtz plane OHP = outer Helmholtz plane i,d = adsorbed ion ih = hy-dratedion oM = charge on the metal electrode o i = charge of adsorbed ions o i = charge of excess hydrated ions in solution. [From Bockris-Devanathan-MuUer, 1963.] 

The potential Ma across the compact layer is a function of the interfadal chaiges ou and = z eFaa shown in Eqn. 5—43  

Assuming that the capacity of the compact layer is constant at potentials near the potential of zero charge, we obtain, to a first approximation, Eqn. 5-46  

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