Nitrogen substitution induced lattice contraction in nickel nanoparticles for electrochemical hydrogen evolution from simulated seawater

Herein, we demonstrate a facile method for the introduction of nitrogen in the lattices of nickel nanoparticles to form NiN_x (x = 0.13, 0.20, 0.27). X-ray absorption spectroscopy reveals the contraction of the Ni-Ni bond and modulated coordination environment after nitrogen introduction. The NiN_0.20 required 87 mV overpotential for −10 mA cm⁻² cathodic current density in simulated seawater. The density functional theory calculations revealed favorable E_H2Oads and ΔG_Hads after N-introduction.