Highly active nickel-cobalt/nanocarbon thin films as efficient water splitting electrodesElectronic supplementary information (ESI) available. See DOI: 10.1039/c6nr06961d

Developing low cost, highly active and stable electrocatalysts for both the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER) using the same electrolyte has remained a major challenge. Herein, we report a novel and robust material comprised of nickel-cobalt nanoparticles coated on a porous nitrogen-doped carbon (NC) thin film synthesized via a two-step pulsed laser deposition technique. The optimized sample (Ni 0.5 Co 0.5 /NC) achieved the lowest overpotentials of 176 mV and 300 mV at a current density of 10 mA cm −2 for HER and OER, respectively. The optimized OER activity might be attributed to the available metal oxide nanoparticles with an effective electronic structure configuration and enhanced mass/charge transport capability. At the same time, the porous nitrogen doped carbon incorporated with cobalt and nickel species can serve as an excellent HER catalyst. As a result, the newly developed electrocatalysts manifest high current densities and strong electrochemical stability in overall water splitting, outperforming most of the previously reported non-precious metal-based catalysts. Highly efficient Ni/Co nanoparticles deposited on N-doped carbon thin films have been developed as bifunctional electrode for enhanced water splitting.