An ultrathin nickel-based film electrodeposited from a Ni-Tris molecular precursor for highly efficient electrocatalytic water oxidation

Water splitting is one of the important and effective routes to produce hydrogen as applicable alternative to conventional fossil fuels. As we all know, oxygen evolution reaction (OER) is a key and restricted part of the overall water-spitting process. Highly efficient electrocatalysts are essential components to accelerate the rate of the OER and lower the overpotential. In this paper, an ultrathin nickel-based film on FTO (NiOx-Tris electrode) was prepared through five cycles of cyclic-voltammetry electrodeposition from a 0.1 M borate buffer solution (pH 9.2) that contained a molecular nickel complex as a precursor. The activity of the as-prepared catalyst film for OER was measured in near-neutral borate buffer solution (0.6 M, pH 9.2), and the results showed that the NiOx-Tris electrode exhibits a better catalytic activity over the catalyst (NiOx-aqua) that was derived from Ni2+ salts. In detail, the NiOx-Tris ultrathin film achieved a stable catalytic current density of ∼5.0 mA/cm2 at 1.3 V versus a normal hydrogen electrode for OER in borate buffer solution.