A simple method was developed in order to measure surface diffusion coefficients in electrochemical systems which involved electrodispersed Au and Pt electrodes. The method was based upon the time dependence of the surface roughness factor of metal overlayers. By assuming a rounded-cap columnar structure for the surface, estimating the thickness via coulometry, and evaluating the roughness factor via conventional voltammetry, it was possible to deduce the surface diffusion coefficient. The activation energy for surface diffusion was estimated to be equal to 14kcal/mol. It appeared that the surface diffusion coefficients in 0.5M H2SO4 were higher than those measured in a vacuum.

C.Alonso, R.C.Salvarezza, J.M.Vara, A.J.Arvia, L.Vazquez, A.Bartolome, A.M.Baró: Journal of the Electrochemical Society, 1990, 137[7], 2161-6