Ni/NiO nanoparticles on a phosphorous oxide/graphene hybrid for efficient electrocatalytic water splitting

Abstract

Herein, Ni/NiO nanoparticles were anchored on phosphorous oxide/graphene for electrocatalytic water splitting. The organophosphate units in graphene nanosheets may facilitate the preferred formation of a surface oxide-modified nickel species with stable reduced electron density at the Fermi level. Efficient catalytic activity and stability in a hydrogen evolution reaction (HER) were obtained. Ni/NiO@HGP_xO_y with a low nickel loading shows an overpotential of 205 mV at a current density of 10 mA cm⁻² and a Tafel slope of 80 mV dec⁻¹, whereas those of its undoped counterpart are 278 mV and 117 mV dec⁻¹, respectively. We proposed that the small particle size, uniform dispersion of Ni/NiO nanoparticles, and electronic effect arising from the interactions between HGP_xO_y and Ni/NiO nanohybrids contribute to the improved electrocatalytic performance.