Self-supported nickel nitride nanosheets as highly efficient electrocatalysts for hydrogen evolution

Ni₃N has been demonstrated as an excellent hydrogen evolution reaction (HER) catalysts that contain active sites with hydrogen adsorption energy. However, the catalytic efficiency of Ni₃N is hindered by its inferior electrical conductivity. Herein, we successfully present an effective strategy to boost the H adsorption capability and HER property of Ni₃N supported by nickel foam is illustrated. Ni₃N nanosheets/nickel foam (Ni₃N NSs/NiF) achieve a super low overpotential of 34 mV at 10 mA cm⁻² and a fairly small Tafel slope of 54 mV dec⁻¹ in 1 M KOH aqueous solution. Focusing on a self-supported electrode structural design, Ni₃N NSs/NiF composites catalysts possess following advantages: (1) abundant exposed edges deriving from thin Ni₃N nanosheets; (2) high conductivity of the entire system generating from metallic metal nitrides integrated by metal substrate; (3) synergistic effect between Ni₃N and nickel foam, and more effective facets to accelerated reaction kinetics. The developed compound is among the most active electrocatalysts based on non-precious catalysts, which expand and enrich the family of materials suitable as efficient HER catalysts.