Interfacial engineering of a Ni3ZnC0.7/VN heterostructure with optimized dual metal sites for alkaline electrocatalytic hydrogen evolution

Abstract

Bimetallic carbide electrocatalysts have been proven to hold great promise for the electrochemical hydrogen evolution reaction (HER). Nevertheless, the effective upgrading of bimetallic carbides for the HER is hampered due to the lack of efficient strategies for the modulation of catalytically active sites. Herein, a novel heterostructured electrocatalyst, comprising Ni₃ZnC_0.7/VN nanoparticles embedded into N-doped carbon nanotubes (Ni₃ZnC_0.7/VN@CNTs), is successfully synthesized via a one-step straightforward calcination protocol. Theoretical and experimental results demonstrate that the synergistic coupling of Ni₃ZnC_0.7 and VN not only enhances the density of interfacial active sites, but also triggers a redistribution of interfacial charges, driven by the work function difference between the two components. This leads to the generation of abundant high-activity Ni–V bridge sites, thereby effectively reducing the H* adsorption–desorption energy barriers and expediting the HER kinetics of Ni₃ZnC_0.7/VN@CNTs. The as-obtained Ni₃ZnC_0.7/VN@CNTs require a remarkably low overpotential of 124 mV to achieve a current density of 10 mA cm⁻² without iR-compensation for the HER, and exhibit outstanding long-term stability for at least 600 h in 1.0 M KOH solution. This work provides a pioneering optimized tactic of dual metal sites for exploiting high-performance bimetallic carbide electrocatalysts that can facilitate the production of sustainable hydrogen.