Electron Transfer Processes at Surfaces

Elementary surface reactions at an electrode involve electron transfer processes. Take as an example the last step in the formation of water in the oxygen reduction reaction (ORR) (or, in the reverse direction, the first step in the water splitting reaction)  

The asterisk,, signifies an adsorption site on the surface, (aq) a species solvated in the aqueous electrolyte, and (U) an electron at a potential U in the electrode. 

we will discuss five important ways in which elementary surface electrochemical reactions may differ from their gas-surface counterparts  

The chemical potential of the electrons entering the reaction is controlled by the 

The surface species, as well as the reactants and products, will be solvated by the electrolyte. Reactant and product solvation in the bulk electrolyte are the same as 

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Many empirical models have been proposed to treat both resonant and Auger electron transfer processes at surfaces. Hagstrum assumed that the rate of neutralization has an exponential dependence on ion/surface distance.He then showed that the ion survival probability, P+, can be approximated by ... 

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