Synergistic N-Doping and Heterointerface Engineering in W₂C/W Nanoarrays Enable pH-Universal Hydrogen Evolution Catalysis

The electrocatalytic hydrogen evolution reaction (HER) by nonprecious metal-based cathodes provides a cost-effective way to store renewable energy as hydrogen fuel. However, pH variation on the cathode surface during electrolysis may lead to performance deterioration. Herein, the heterostructure electrode composed of nitrogen-doped ditungsten carbide/monolithic tungsten interface (N–W2C/W) is developed. The as-obtained electrode showed superior HER performance in pH-universal conditions, achieving −10 mA cm–2 with small overpotentials of 90, 90, and 82 mV in acidic, neutral, and alkaline electrolytes, respectively. Moreover, the electrocatalyst shows negligible performance decay after 24 h at the current densities of even −500 mA cm–2. Theoretical studies reveal that the interface W site exhibits suitable Gibbs free energy of hydrogen adsorption. Moreover, the unique interfacial structure provides synergistic active sites for water dissociation. This work provides an approach to design an interfacial structure based on nonprecious metals for highly efficient HER electrocatalysis.