Influence of anion adsorption on the step dynamics on Au(111) electrodes

Using scanning tunneling microscopy, we have investigated the step dynamics on an Au(lll) single crystal electrode in aqueous electrolytes. Our studie s focused on the influence of specifically adsorbed anions and the anion co ncentration on the mobility of gold atoms at monatomic-high step edges. The experiments were performed in chloride-containing and chloride-free H2SO4 electrolytes. From the quantitative analysis of equilibrium step fluctuatio ns we deduce the dominant mass transport mechanisms as a function of the el ectrode potential and as a function of the anion concentration. Estimates o f the energies involved in the mass transport are presented. (C) 2000 Elsev ier Science B.V. All rights reserved.