Adsorption Isotherms for Intermediates Formed by Charge Transfer

Adsorption Isotherms for Intermediates Formed by Charge Transfer 

It represents the equilibrium between a species in solution and the same species adsorbed on the surface. The fractional surface coverage is defined as 

This definition implies that 0 0 1, namely that adsorption is limited to a monolayer, which is valid if the bonding of the first layer of the adsorbate to the substrate is much stronger than that of subsequent layers to each other. Multilayer adsorption can occur under suitable conditions, but will not be discussed here. 

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ADSORPTION ISOTHERMS FOR INTERMEDIATES FORMED BY CHARGE TRANSFER... 

We saw earlier (cf. Section 19) that the potential dependence of adsorption of intermediates formed by charge transfer affects the kinetics of electrode reactions. We have worked out the kinetic parameters for a few mechanisms under so-called Langmuir and Temkin conditions (i.e., when the Langmuir and the Temkin isotherms are applicable, respectively). Here we shall derive the appropriate kinetic equations for the combined adsorption isotherm. 

The adsorption isotherms discussed in Section. 11.1 describe the potential dependence of the fractional surface coverage, 0. For intermediates formed in a charge-transfer process, (cf. Eq. (11.7)), the fractional coverage is associated with a Faradaic charge gp that is given by... 

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