Interfacial engineering of Ni/WC heterostructure electrocatalyst for highly efficient hydrogen evolution reaction in all pH electrolyte

The development of high-performance electrocatalyst for sustainable hydrogen production is a necessary prerequisite for rapid progress of hydrogen economy. The integration of multi-interfaces in binary-component heterostructures for robust HER electrocatalysts has been proved to be a feasible strategy for optimizing the electronic structure and H adsorption/desorption of active sites and facilitate their HER kinetic. Herein, a series of N-doped carbon coated binary-phase Ni/WC heterostructure (Ni/WC@C) were prepared by annealing a mixture of Ni-substituted POMs with serial atomic ratio of Ni:W (2:3, 4:9 and 1:11) and dicyandiamide. By virtue of abundant and homogeneously distributed dual-phase Ni/WC interface with high intrinsic activity, Ni ₄W ₉ @C originated from the precursor with Ni:W atomic ratio of 4:9 delivers ultralow overpotential of 38 mV to reach the current density of 10 mA cm ⁻² and Tafel slope of 43 mV/dec in 0.5 M H ₂SO ₄ electrolyte. This prominent performance can be achieved in all-pH eletrolytes. By virtue of the ultra-stable Ni/WC interfaces and the wrapping effect in N-doped carbon shell, Ni ₄W ₉ @C shows robust electrochemical durability and structural stability in all acidic, neutral, and alkaline media. This work provides a potentially powerful interface engineering strategy for the design and performance improvement of multi-component HER electrocatalysts.