Enhanced diffusion of surface atoms at metalrelectrolyte interface under potential control

We have investigated the surface self-diffusion coefficient DS.on Ag 100.in aqueous 50 mM H2SO4 solution using electrochemical atomic force microscopy ECAFM.. The results were compared with those observed on Au 100.. The DS values of Ag 100.increased exponentially with potential between y50 and 350 mV vs. normal hydrogen electrode, NHE.. From the DS–E relationship, we propose that the activation energy of surface diffusion decreases because of the surface excess charge. We also found that the DS values on Ag 100.were a hundred times larger than those on Au 100.within the potential range from 150 to 350 mV vs. NHE.. q1998 Elsevier Science B.V. All rights reserved