The Anodic Oxidation of Nickel in Alkaline Media Studied by Spectroelectrochemical Techniques

The anodic oxidation of nickel has been studied employing in situ near normal incidence reflectance spectroelectrochemical and other electrochemical techniques. Results indicate that the Ni(II) hydroxide layer on the nickel electrode undergoes a further oxidation to Ni( III ) oxide/hydroxide with the proton diffusion process as a limiting step. Proton diffusion coefficients during the oxidation of Ni(II) hydroxide range from ; as determined from cyclic voltammetric and chronoamperometric measurements. Chronoabsorptometric results indicate that at short time the semi‐infinite diffusion model is operative, while at longer times the finite diffusion model takes over. This is consistent with the thin layer cell electrochemistry model for the nickel hydroxide oxidation.