An X-ray absorption fine structure study of the initial stages of the anodic oxidation of silver

The grazing incidence X-ray absorption fine structure technique was used for the in situ investigation of the initial stages of the anodic oxidation of silver electrodes in 1M NaOH. The reflectivity fine structure of the oxide covered electrode was measured for several potentials corresponding to different oxide thicknesses. The comparison of the experimental data with those of model calculations enabled the extraction of short-range order structural information about the anodic overlayer. Considerable changes of the reflectivity fine structure data are observed for silver(I) oxides formed at different potentials. In addition, the potentiostatic oxide layer formation as well as the electrochemical reduction causes significant changes of the X-ray reflectivity of the silver working electrode. Even the reduction of thin oxide layers of about 2-5 nm thickness causes a microroughening of the electrode surface.