Utilization of Special Potential Scan Programs for Cyclic Voltammetric Development of Different Nickel Oxide-Hydroxide Species on Ni Based Electrodes

Abstract

Special potential scan programs were designed for cyclic voltammetric development of β-NiOOH or γ-NiOOH/ β-NiOOH mixtures on the surface of nickel or nickel-chromium (80:20) alloy electrodes in NaOH 0.10 M. The programs consisted on changing the anodic or cathodic switching limit to facilitate the chemical reactions taking place either between Ni(II) hydroxides or between Ni(III) oxides-hydroxides. The electrochemical charge density under the oxidative wave, observed at Ni or Ni-Cr electrode surfaces at approximately 0.48 V (vs SCE), remained almost constant with the number of cv cycles after approximately 600 cv cycles at 0.050 V/s. Thus, it can be suggested that a stable proportion of Ni(II)/Ni(III) oxides-hydroxides was obtained on the electrode surfaces. The relative amounts of β-NiOOH or γ-NiOOH species were calculated from the electrochemical charges under their reduction waves in the voltammetric experiments. Higher charge densities were always obtained with Ni-Cr alloy electrodes as compared to pure Ni electrodes. Linear relationships were obtained in our study on the dependence of the oxidative peak current with the square root of the scan rate at a scan rate range between 0.01 V/s and 0.16 V/s.

Back‐Illuminated Si‐Based Photoanode with Nickel Cobalt Oxide Catalytic Protection Layer

“…Kim et al [39] also reported that the shift in the Ni 2 + /3 + redox features in the negative direction (> 50 mV) is induced by the presence of Co in the Ni hydrous oxide lattice. In agreement with the previous observations by other groups, [10,38,39] no discernible voltammetry features associated with the Co 2 + /3 + redox couple can be identified for the composite Ni-Co oxide film. Despite of a harmony with previous observations, the precise effect on the catalytic mechanism remains unknown.…”

“…Marioli and co-workers [38] observed that this negative shift takes place for Ni-Cr binary oxide films, whereas single-component nickel oxide showed only an anodic redox peak shift. Kim et al [39] also reported that the shift in the Ni 2 + /3 + redox features in the negative direction (> 50 mV) is induced by the presence of Co in the Ni hydrous oxide lattice.…”

A high-performance, bifunctional oxygen electrode catalysed with palladium and nickel-iron hexacyanoferrate

“…The peak at c.a. +0.45 V vs. Hg/HgO is caused by nickel oxidation [37] and slightly masks the onset of oxygen evolution, which begins at +0.33 V vs. Hg/HgO. For the OER, the Ni/Fe + Pd air electrode outperforms all the other air electrodes in terms of current density.…”

Kinetics of the oxygen evolution reaction on NiSn electrodes in alkaline solutions

“…3a). This new wave was ascribed to the reduction of γ-NiOOH [47]. Thus, the charges obtained under cathodic peaks II and III represent the amount of β-NiOOH or γ-NiOOH produced during the positive going potential sweep or anodic polarization during the OER.…”