Double-catalytic-site engineering of nickel-based electrocatalysts by group VB metals doping coupling with in-situ cathodic activation for hydrogen evolution

The hydrogen evolution reaction (HER) in alkaline media is limited by poor-proton environment with the water dissociation step. Herein, we report a double-catalytic-site construction strategy for nickel-based materials (e.g., sulfides, selenides, phosphides and oxides) for HER, utilizing group VB metals (V, Nb or Ta) doping coupled with the subsequent in-situ cathodic activation (ICA). For V-doped nickel sulfide, ICA creates Ni-V oxides species as new active sites for water dissociation. Moreover, V dopants enhance the intrinsic activity of nickel sulfide by the electronic interaction between Ni and V during the ICA process. As a result, the double-catalytic-site system composed of Ni V sulfides-oxides hybrid achieves 4-fold higher intrinsic activity and 15-fold larger current density at the overpotential of 300 mV than those of pristine nickel sulfide. Our work may open up a new avenue for designing multi-site systems, which may be promisingly applied for other transition metal materials in the electrolysis field.