Effect of Electrochemical Factors on Formation and Reduction of Silver Oxides

Polarization of silver in NaOH solution with various electrochemical parameters was investigated by cyclic voltammetry and scanning electron microscope. The resulting cyclic voltammograms reveal that the observed midpoint potential and current density of the peaks during the anodic scan and the reversed scan can be shifted significantly depending on scan rate and NaOH concentration. The shapes of the peaks in the first cycle were different from the other cycles of silver’ cyclic voltammetry. The peaks were barely dependent of scan rate since the second cycle. Two layers of Ag2O, which owed to the formation of dual anodic peaks of Ag2O, appeared during the anodic scan of silver’ cyclic voltammetry. Two secondary anodic peaks were formed if the scan rate was no less than 20 mV/s and NaOH concentration was no less than 0.5 mol·L-1 The trenched images by focus ion beam system explored that the depth of the polarized silver was approximately 810 nm after three cycles with a scan rate of 10 mV/s in 1 mol·L-1 NaOH solution. The images of the polarized silver clarified the formation and shifts of the peaks in silver’s cyclic voltammetry.