Well-dispersed ultrasmall VC nanoparticles embedded in N-doped carbon nanotubes as highly efficient electrocatalysts for hydrogen evolution reaction

Abstract

The rational design and synthesis of ultrasmall metal-based electrocatalysts using earth-abundant elements for the hydrogen evolution reaction (HER) have been widely considered as a promising route for achieving improved catalytic properties. Herein, a metal-triggered confinement strategy to prepare well-dispersed ultrasmall VC nanoparticles (∼3 nm) embedded within N-doped carbon nanotubes (VC@NCNT) by using Co metal as the crystallization promoter is reported. When used as a HER electrocatalyst for water splitting, the resultant VC@NCNT catalyst exhibits low overpotentials (acid medium: 161 mV; alkaline medium: 159 mV; neutral medium: 266 mV) for driving a current density of 10 mA cm⁻², remarkable durability at least for 100 h, and ∼100% faradaic yield in both acid and alkaline media. Such excellent electrocatalytic HER performance is ascribed to the synergistic contribution of high pyridinic N-doping, outstanding conductivity of carbon nanotubes, and exposed abundant catalytic active sites of ultrasmall VC nanoparticles.