Enhanced water oxidation activity of 3D porous carbon by incorporation of heterogeneous Ni/NiO nanoparticles

Abstract

Considering the expensive and rare property of noble-metal based materials, great efforts are made to synthesize high-activity, economical and electrochemically stable catalyst for oxygen evolution reaction (OER) in harsh alkaline. Heterogeneous materials coupled by transition metal and carbon exhibit high capability for OER in recent years. Here, three-dimensional (3D) porous carbon coupled with Ni and NiO hybrid nanoparticles (Ni-Cx-y, x and y are annealing temperature and time, respectively) is synthesized via high temperature pyrolysis and air annealing treatment. Redox reaction between carbon atoms and nickel ions during synthesis could achieve a high-level graphitization, which greatly enhances the corrosion resistance of catalyst in alkaline solution. The overpotential at 10 mA cm−2 and Tafel slope of Ni-C500-20 achieve 353 mV and 97 mV dec–1, respectively. Increased defects and intrinsic activity induced by air annealing process and synergistic effect between carbon, Ni and NiO give rise to the enhanced OER performance of as-prepared catalyst, as confirmed by in-situ Raman spectra. The catalyst conforms to sustainable and economic development concept, being a potential material for OER.