Electrocatalytic water oxidation by a nickel oxide film derived from a molecular precursor

Abstract

In this study, we fabricated a NiOx film by electrodeposition of an ethanediamine nickel complex precursor (pH = 11) on a fluorine-doped tin oxide substrate. The resulting film is robust and exhibits high catalytic activity for electrochemical water oxidation. Water oxidation is initiated with an overpotential of 375 mV (1 mA/cm2) and a steady current density of 8.5 mA/cm2 is maintained for at least 10 h at 1.3 V versus the normal hydrogen electrode. Kinetic analysis reveals that there is a 2e−/3H+ pre-equilibrium process before the chemical rate-determining step. The low-cost preparation, robustness, and longevity make this catalyst competitive for applications in solar energy conversion and storage.