Metallic Ni₃N/Ni heterostructure for efficient hydrogen evolution reaction

The utilization of precious metal materials is currently recognized as a prominent approach for improving the effectiveness of catalysts in hydrogen evolution reaction (HER). However, it is imperative to explore alternative electrocatalysts built of non-precious transition metals to achieve cost-effectiveness and cater to extensive industrial applications. Herein, a Ni₃N/metallic Ni (Ni₃N/Ni) heterostructure is designed and prepared by a programmed thermal nitridation technique. The optimized hydrogen adsorption ability and metallic conductivity of Ni₃N/Ni enable excellent hydrogen evolution properties. The robust electronic interactions between the Ni₃N and metallic Ni phases result in the transport of electrons from Ni to Ni₃N across the heterointerface, which can efficiently regulate the electronic states of the catalyst. As a consequence of this, the Ni₃N/Ni electrocatalyst has exceptional catalytic capabilities in alkaline HER. An overpotential of 144 mV is required, which is the minimum, to generate a current density of 10 mA cm⁻². At the same time, it only exhibits a minor Tafel slope of 107 mV dec⁻¹. Simultaneously, it exhibits a notable degree of utilization efficiency for energy conversion, as seen by its Faraday efficiency of 99.8 %. Furthermore, a minimal overpotential movement of about 14 mV following 6000 cycles at 10 mA cm⁻² is indicated, exhibiting exceptional durability. The findings of this study offer novel perspectives on the optimization of surface electron distribution states in cost-effective nickel-based heterostructured electrocatalysts, to enhance their efficiency in alkaline HER. © 2024 Hydrogen Energy Publications LLC.