Tuning the Electronic Structure of the CoP/Ni2P Nanostructure by Nitrogen Doping for an Efficient Hydrogen Evolution Reaction in Alkaline Media

As one of the most sustainable, efficient, and cleanest ways for hydrogen production, electrochemical water splitting relies heavily on cost-efficient and stable electrocatalysts. Herein, a self-supported and nitrogen-doped hybrid CoP/Ni2P was synthesized through a simple two-step hydrothermal process followed by low-temperature phosphorization and nitridation (N-CoP/Ni2P@NF). Both experimental and density functional theory calculation results suggest that nitrogen doping can tune the electrical structure of the CoP/Ni2P heterostructure and thus optimize the free energy of adsorbed H on the surface of N-CoP/Ni2P@NF and accelerate the electronic transport activity. The prepared N-CoP/Ni2P@NF exhibits excellent electrocatalytic hydrogen evolution reaction (HER) performance, which merely requires an overpotential of -46 mV at -10 mA cm(-2) and shows a negligible decay after a long durability test for 72 h in alkaline (1.0 M KOH) media. Consequently, this work supplies a novel strategy with great potential for designing transition metal phosphate-based catalysts with high HER performance.