We have investigated recrystallization of an electrochemically roughened silver electrode surface in Ar-saturated water, using cyclic voltammetry (CV), Auger electron spectroscopy (AES), and tapping mode atomic force microscopy (TMAFM). Comparison of CVs before and after 92 h relaxation in water indicates that surface flattening occurs at room temperature when the roughened Ag is in contact with water. An AES spectrum of the Ag surface before the relaxation shows that chlorine still remains on the surface, probably in the form of AgCl. We determined the roughness exponents (α) for the roughened Ag surfaces before and after the relaxation from the slopes of the linear regions observed in plots of log (the interface width) vs log (length scale) calculated from TMAFM data. At larger length scales than the average Ag nodule size, αs were 0.50±0.02 and 0.64±0.02 for the roughened surfaces before and after the relaxation, respectively. These results suggest that the scaling theory may be applicable to the recrystallization process at the submicron level.

We have constructed a scanning tunneling microscope (STM) for electrochemical studies. Using the STM, we investigated an electrochemically treated surface of a polycrystalline silver electrode in a 0.1 M KCl solution. The STM images of the Ag electrode in the solution exhibited large asymmetric peaks resulting from the large asymmetric current spikes. We found that a plot of the current vs t -1/2, where t is time, for a single current spike satisfies a linear relation, i.e., the Cottrell equation. Thus, a diffusion-controlled electrochemical reaction was observed at a specific region by the STM.

SUMMARY We have combined a three‐electrode cell arrangement with a scanning tunnelling microscope (STM) to image the surfaces of polycrystalline noble metal electrodes under potentiostatic conditions. STM imaging was made in the potential range where a tip and the electrodes are ideally polarized. We have observed on a submicron scale that the electrochemically roughened Ag electrode surface relaxed over times of 40 min at −0·16 V versus SCE in 0·1 m KCl. We have also imaged a dynamic process (formation and dissociation) of the submicron‐scale reconstruction of the Au electrode subjected to electrochemical oxidation‐reduction cycles. The results can be explained by the absorption of Cl− ions and the surface diffusion of adatoms or clusters. STM imaging under potentiostatic control leads to the discovery of phenomena occurring at solid metal/electrolyte interfaces.

We have studied the kinetic mechanisms in recrystallization of an electrochemically roughened silver electrode surface in Ar-saturated water at room temperature using dynamic scaling theory and tapping mode atomic force microscopy (TMAFM). We observed dynamic scaling behavior during the recrystallization. The roughness (α) and growth (β) exponents measured were α = 0.95 ± 0.05 and β = 0.16±0.04 for the scale length (L) < the average diameter of Ag nodules (d), and α = 0.61±0.05 and β = 0.20±0.05 for L > d. These scaling exponents are relatively close to the predictions (β = 0.25, 0.20) of conservative models where surface diffusion is the main mechanism of mass transport in determining a growing surface morphology.

We have combined a three-electrode cell arrangement with a scanning tunnelling microscope (STM) to image the surfaces of polycrystalline noble metal electrodes under potentiostatic conditions. STM imaging was made in the potential range where a tip and the electrodes are ideally polarized. We have observed on a submicron scale that the electrochemically roughened Ag electrode surface relaxed over times of 40 min at -0-16 V versus SCE in 0.1 M KCl. We have also imaged a dynamic process (formation and dissociation) of the submicron-scale reconstruction of the Au electrode subjected to electrochemical oxidation-reduction cycles. The results can be explained by the absorption of C1-ions and the surface diffusion of adatoms or clusters. STM imaging under potentiostatic control leads to the discovery of phenomena occurring at solid metal/electrolyte interfaces.