Charge distribution modulation of hollow flower-like tungsten doped nickel nitride for alkaline hydrogen oxidation

Abstract

Exploring efficient nickel (Ni)-based catalysts for alkaline hydrogen oxidation reaction (HOR) to replace platinum group metal (PGM) is highly essential for the development of anion exchange membrane fuel cells. Nevertheless, the HOR activity of Ni is far away from PGM owing to the strong hydrogen adsorption. Herein, the tungsten-doped nickel nitride (W-Ni3N) with modulated local charge distribution and hollow flower structure is presented to improve the HOR performance. Mechanism studies reveal that W doping induces the redistribution of local charge around Ni sites due to the electron transfer from Ni to W, which strengthens the hydroxyl adsorption and simultaneously weakens hydrogen adsorption. Benefitting from the optimized adsorption of HOR intermediates and hollow flower structure, W-Ni3N exhibits improved intrinsic activity and mass activity, which are 1.7 and 10 times higher than that of pure Ni3N, respectively. This work presents a promising way to design cost-effective electrocatalysts by fine-tuning the electronic structure.