Rational design of self-supported Cu@WC core-shell mesoporous nanowires for pH-universal hydrogen evolution reaction

Cu@WC core-shell nanowires, as the WC-based materials with Pt-like electronic configurations around the Fermi level, have been successfully fabricated via chemical oxidation and electro-reduction processes followed by magnetron sputtering of WC for pH-universal hydrogen evolution reaction (HER). The Cu@WC catalyst showed low overpotentials of 92, 119 and 173 mV at 10 mA cm⁻² in acidic, alkaline and neutral conditions with high exchange current densities. The core-shell structure was verified to increase the WC's carrier density with the interfacial, strongly delocalised electrons under the external electric potential and matched work functions between Cu and WC preserving the high level of Pt-like electrons in WC. The ΔG_H^* calculations demonstrated that the lattice mismatch between WC and Cu modifies the atomic and electronic structures of WC and weakens the hydrogen bond during absorption leading to enhanced HER performance. This work provides a deep insight into the WC-based core-shell catalysts for pH-universal HER.