Fractals and rough electrodes

The recent literature on the effect of electrode roughness on electrochemical measurements is reviewed. Some implicit assumptions and approximations in the model of Nyikos and Pajkossy are examined, as well as its extension to include charge transfer processes. Explicit expressions are then presented for the effects of diffusion and of coupled homogeneous chemical reactions on the electrode impedance measured at the equilibrium potential. Finally, it is shown that (and how) the apparent transfer coefficient depends on electrode roughness.