Application of transmission Mössbauer effect spectroscopy to the study of electrocatalysis and adsorption phenomena at the nickel hydroxide electrode

Abstract
Mössbauer parameters for ferric hydroxo forms in alkaline matrices, ferric oxyhydroxide and its admixture at the nickel hydroxide electrode surface as well as for ferric hydroxo species absorbed at nickel hydroxides from strongly alkaline solutions have been compared. The feasibility of transmission Mössbauer spectra acquisition for the adsorbed species in the presence of dissolved forms (e.g. in situ) is based on the principle that the latter give no Mössbauer effect at room temperature owing to their diffusional mobility, while the former, being fixed at the adsorbent surface, have been shown to exhibit a sufficient resonant absorption. The effects of adsorption and water have been noted. Some questions connected with anodic oxygen evolution electrocatalysis by iron species involved in the anodic process at the nickel hydroxide electrode are also discussed.