Interface engineered NiMoN/Ni₃N heterostructures for enhanced alkaline hydrogen evolution reaction

The development of low-cost and high-efficiency hydrogen evolution reaction (HER) catalysts for alkaline electrolysis is beneficial in the storage of renewable electricity through hydrogen energy. Metallic Ni₃N is regarded as an excellent catalyst for water oxidation, but the HER activity in alkaline solution is subjected to its poor water dissociation ability and strong hydrogen adsorption. In this work, we report a highly active and durable alkaline HER electrocatalyst of NiMoN/Ni₃N heterostructures by interface engineering. The introduction of NiMoN can not only effectively accelerate the water dissociation process, but also optimize the binding energy of hydrogen via interfacial interaction with Ni₃N. In addition, the porous nanosheet arrays assembled by plenty of nanoparticles can provide more exposed active sites and accelerate the reaction kinetics. The heterostructured electrocatalyst exhibits an extremely low overpotential of 28 mV at a current density of 10 mA cm⁻² and a small Tafel slope of 49 mV dec⁻¹. The design concept of interface engineering could offer a new paradigm for the development of superior HER catalysts toward alkaline electrolysis.