Substitutional Doping Engineering toward W₂N Nanorod for Hydrogen Evolution Reaction at High Current Density

Abstract

Transition metal nitrides and elemental doping are effective methods to enhance the catalytic activity of hydrogen evolution reaction (HER) at a high current density. Herein, Ni-W2N@NF was synthesized to exhibit excellent HER performance in an alkaline environment. Not only theoretical but also experimental analyses prove that Ni enters the W2N lattice in the form of substitutional doping. Ni-doped W2N optimizes the free energy of hydrogen adsorption and hydroxide adsorption. Thus, the HER kinetics are accelerated. Therefore, the synthesized Ni-W2N@NF achieved an industrial high current density of 2000 mA cm–2 in 1 M KOH with a small overpotential of 317 mV. The HER activity of Ni-W2N@NF is superior to those of most reports. What is more, the obtained catalyst achieves a current density of 1500 mA cm–2 in an alkaline seawater solution with an overpotential of only 345 mV and exhibits excellent cycling stability. This work will offer a feasible idea for a designing platinum group metals free metal as an effective catalyst for HER reaction under an industrial large current in an alkaline solution.