Reactive-template fabrication of porous NiO nanowires for electrocatalytic O2 evolution reaction

Abstract

One-dimensional nickel oxide nanowires (NiO NWs) with lengths of ∼8 μm and widths of ∼100 nm were synthesized by a reactive-template directed solvothermal route using selenium nanowires (Se NWs) as the sacrificial template. The electrocatalytic O₂ evolution reaction (OER) was studied on polycrystalline NiO NWs using cyclic voltammetry (CV) and linear sweep voltammetry (LSV) measurements in alkaline media. Nickel oxide nanoparticles (NiO NPs) with size distributions of 50–100 nm were also synthesized by a facile hydrothermal method for comparative electrocatalytic evaluation with the porous NiO NWs. In the present case we demonstrate the applicability of spin coating techniques to fabricate the porous NiO NWs on a fluorine doped tin oxide (FTO) glass electrode. The porous NiO NW coated FTO (NiO NWs/FTO) exhibit higher electrocatalytic activity and higher current efficiency of OER than that of NiO NP coated FTO (NiO NPs/FTO). The electrocatalytic properties of the NiO NWs are discussed in the context of earlier reports based on the NiO catalyst. The as-prepared NiO NWs represent a new class of non-precious catalysts for OER, which demonstrates promise for future applications in alkaline water splitting.