Electrochemical surface processes

Abstract

Usually electrochemical processes involve an exchange of electrons or ions between the electrode and the electrolyte. The driving force is the difference in the electrochemical potential of the transferring species, and therefore depends on the electrode potential. However, there exist processes which take place on the electrode surface only, without exchange of charge with the solution. Nevertheless, these processes often show a strong dependence on the electrode potential. At a first glance, this may seem strange: the electrode surface is equipotential, and hence a change of the potential should not affect the driving force directly. However, a change of potential entails a change of the surface charge density, and hence of the electric field in the double layer. This field interacts with local dipole moments on the surface, and may thereby affect surface processes. In this chapter, we will discuss a few examples.