CoS2 nanowires supported graphdiyne for highly efficient hydrogen evolution reaction

Abstract

Abstract 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 CoS2 nanowires have been successfully activated through constructing Graphdiyne-CoS2 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 sp1 hybridized carbons and unsaturated planar sulfurs. In addition, DFT simulations reveal the synergetic effects of the sp1 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-CoS2 heterojunction nanocomposites exhibit superior HER catalytic performance with low overpotential of 97\xa0mV at 10\xa0mA\xa0cm−2, and the Tafel slope of 56\xa0mV\xa0dec−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.