Electrosorption on metal electrodes

It was first recognized by Lorenz and Salie [159] that when an ion is adsorbed on an electrode the charge that is transferred need not be a whole multiple of the unit charge. This partial charge transfer can be represented by the stoichiometric 

There is no direct way of measuring the partial charge transfer A, the most direct experimental evidence comes from NEXAFS experiments. It is related to the electrosorption valency [160]. 

We consider a nonadsorbing suporting electrolyte of high concentration, so that the charges in the interfacial region are well screened. Then, we define the electrosorption valency as 

Electrostatic potential at a metal/electrolyte interface gives the effect of the ionic charge number, z, which is transported over a fraction g of the potential difference 

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