Artificial heterointerfaces of defect-rich Ni and amorphous/crystalline MoN enable efficient hydrogen evolution reaction

Abstract

Developing highly-active and robust electrocatalysts for the hydrogen evolution reaction (HER) is extremely desirable for hydrogen production but remains highly challenging. Herein, we reported a rational strategy to fabricate a novel metallic heterostructure composed of defect-rich nickel and amorphous/crystalline molybdenum nitride anchored on a carbon matrix (MoN/Ni@C) as a superior HER electrocatalyst. Owing to the electronic structural modulation of the interfacial synergy of the defects and phase engineering, the MoN/Ni@C exhibits a low HER overpotential of 27 mV at 10 mA cm−2 and a small Tafel slope of 73 mV dec−1 in 1.0 M KOH solution, without any distinct attenuation after 180 h of operation. Density functional theory calculation results demonstrate that the interfacial electron transfer leads to a distorted Ni surface incorporation of the MoN phase, achieving the optimal thermoneutral hydrogen adsorption free energies (ΔG*H) of Mo and Ni active sites. Meanwhile, the amorphous/crystalline structure in the MoN phase exposes more active sites and promotes structural stability. This work provides new insights into designing heterogeneous interfaces of non-noble-metal-based electrocatalysts with superior HER activities.