Ultrasmall VN/Co heterostructure with optimized N active sites anchored in N-doped graphitic nanocarbons for boosting hydrogen evolution

Interface engineering is deemed as an effective approach to optimize the electronic structure of catalytically active sites in electrocatalysts for boosted hydrogen evolution reaction (HER). Herein, a novel ultrasmall VN/Co heterostructure anchored in N-doped graphitized nanocarbons (VN/Co@GNC) is successfully synthesized by a simple calcination protocol. Benefiting from the abundant reactive sites on the interface of ultrasmall heterostructure, enhanced N active sites of VN coupled with Co nanoparticles, as well as excellent conductivity of N-doped graphitized nanocarbons as the scaffold, the resulting VN/Co@GNC material exhibits outstanding electrocatalytic HER performance, delivering the current density of 10 mA/cm² at a quite low overpotential of 155 mV without iR-compensation, and retaining the catalytic durability for at least 565 h (∼23.5 days) in 1 M KOH solution. The superior catalytic activity and ultrastability of VN/Co@GNC electrocatalyst lay a solid foundation for its commercial applications toward the hydrogen fuel production.