CoS2 nanowires supported graphdiyne for highly efficient hydrogen evolution reaction

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Planar unsaturated sulfurs in (211) facet of the CoS 2 nanowires have been successfully activated through constructing Graphdiyne-CoS 2 heterojunction nanocomposites as efficient electrocatalyst toward HER. • The electron transfer between two-dimensional planes greatly enhances the catalytic activity of sulfur active sites. • DFT simulation confirms the reaction process mechanism. • Outstanding HER catalytic performance with good stability has been achieved. • Provide new insights and paves the way for the further efficient transition metal disulfides catalyst manufactures. Transition metal sulfides are an important category for hydrogen evolution reaction (HER). However, only few edge unsaturated sulfurs functionalize as catalytic sites, which has dramatically limited the catalytic activity and stability. In this work, planar unsaturated sulfurs in (211) plane of the CoS 2 nanowires have been successfully activated through constructing Graphdiyne-CoS 2 heterojunction nanocomposites. The corresponding electrons transfer energy barriers for these planar unsaturated sulfurs have been significantly diminished, which are induced by the synergetic effects of the sp 1 hybridized carbons and unsaturated planar sulfurs. In addition, DFT simulations reveal the synergetic effects of the sp 1 hybridized carbons and unsaturated planar sulfurs can promote electron transfer kinetics of the key step, Volmer-Heyrovsky step, of the reaction. As expected, the Graphdiyne-CoS 2 heterojunction nanocomposites exhibit superior HER catalytic performance with low overpotential of 97 mV at 10 mA cm −2 , and the Tafel slope of 56 mV dec −1 . Furthermore, the heterojunction shows outstanding stability as well due to the protection of the Graphdiyne (GDY). The approach thus paves the way for the further efficient transition metal disulfides catalyst manufactures.