The thermodynamics of electrochemical annealing

We show that on solid electrodes held at constant potential in an electrolyte all defect formation energies and activation energies for surface transport become potential dependent. The rapid smoothening of rough metal electrodes for (mostly) positive electrode potentials (electrochemical annealing) is therefore the consequence of the specific thermodynamic boundary condition of constant electrode potential. The potential dependence can be related to the surface charge density and the dipole moments of the defects. With dipole moments calculated by ab initio methods the theory is applied to experimental data on two-dimensional Ostwald ripening on Au(1 00) electrodes. The theory is further discussed in the context of other experiments. (c) 2005 Elsevier B.V. All rights reserved.