Cu-induced interface engineering of NiCu/Ni3N heterostructures for enhanced alkaline hydrogen oxidation reaction

Abstract

Constructing well-defined interfaces in catalysts is a highly effective method to accelerate reactions with multiple intermediates. In this study, we developed a heterostructure catalyst combining fcc NiCu and hcp Ni₃N, aiming at achieving superior performance in alkaline hydrogen electrocatalysis. The NiCu/Ni₃N not only overcomes the inadequate hydroxyl binding energy performance of NiCu alloys but also solves the problems of insufficient active sites found in most Ni/Ni₃N. Experimental results and density functional theoretical calculations reveal that the formation of heterostructure significantly depends on the amount of Cu. This approach effectively prevents the side effects of increased catalyst particle size, typically resulting from the high temperatures and prolonged reaction times required for conventional synthesis of Ni/Ni₃N. The interface of this heterostructure induces a distinctive overlapping effect that enhances the adsorption of water and lowers the energy barrier for the rate-determining step. The NiCu/Ni₃N catalyst shows an impressive activity of 71.8 mA mg⁻¹ at an overpotential of 50 mV, a 14.7 times efficiency enhancement compared to pure Ni and comparable to that of low-loaded commercial Pt/C. This research highlights the potential of NiCu/Ni₃N in advancing catalyst development.