Vanadium self-intercalated C/V1.11S2 nanosheets with abundant active sites for enhanced electro-catalytic hydrogen evolution

A novel and highly active vanadium self-intercalated C/V 1.11 S 2 nanosheets with abundant active sites are fabricated by a simple hydrothermal-calcinations method. The structures and morphology of C/V 1.11 S 2 nanosheets were characterized by XRD, SEM, XPS and TEM. Particularly, PVP (polyvinylpyrrolidone) was used as surfactant to control the morphology of vanadium sulfide and carbon source to reduce the vanadium sulfide into vanadium self-intercalated V 1.11 S 2 phase with rich active sites. The C/V 1.11 S 2 nanosheets showed an excellent electrocatalytic activity for hydrogen evolution reaction, including a low onset potential of 15 mV vs. RHE (reversible hydrogen electrode), small Tafel slope of 51 mV dec −1 , as well as extraordinary catalytic stability. The first-principle calculations further confirmed that the V 1.11 S 2 has a much lower Gibbs free energy for hydrogen adsorption (ΔG H ) than that of VS 2 . The enhanced HER performance can be contributed to the unique vanadium self-intercalated structures, nanostructured morphology and rich sulfur defects of the obtained C/V 1.11 S 2 nanosheets. We believe that the C/V 1.11 S 2 can be used as electrocatalyst in chemical engineering industry and our method provides guidance on the fabrication of other defective transition-metal dichalcogenides to improve their catalytic performances.