Thermodynamics of the adsorption at electrodes

Obviously AGad depends on the strength of the solvent-surfaee and the adsorbate-surfaee interaction in addition S-S-, A-A- and S-A-interactions contribute. Various simplifications are possible [74Tra]. As a further complication the electrical field being always present (except at at the electrode/solution-interface has to be considered. Consequently the free enthalpy of adsorption can be split into a chemical part and an electrical part  

This separation assumes, that the type of interaction causing is not influenced by the electric 

Proper definition of the reference state is essential for the compatibility of values of the free enthalpy of adsorption results in values of obtained by various authors and with different methods [87Jas, 

The strength of the adsorptive interaction as expressed in values of AG jj depends on the mode of interaction between the adsorbate molecule and the electrode surface. Weak adsorption (physisorption) is based mostly on van-der-Waals-interactions. It shows t5q)ically values of AG jj - 20 kJ mol Stronger 

---