A vertical-oriented WS2 nanosheet sensitized by graphene: an advanced electrocatalyst for hydrogen evolution reaction

Abstract

Electrocatalytic hydrogen production at low overpotential is a promising route towards a clean and sustainable energy. Layered transition metal dichalcogenides (LTMDs) have attracted copious attention for their outstanding activities in hydrogen evolution reaction (HER). However, the horizontally laid nanosheets suffer from a paucity of active edge sites. Herein, we report the successful synthesis of vertical-oriented WS₂ nanosheets through a hydrothermal method followed by a facile sulfurization process. Furthermore, the surface of synthesized WS₂ nanosheets was decorated by ultrathin reduced graphene oxide (rGO) nanoplates. This is achieved for the first time by bringing the rGO on the surface of vertical-oriented WS₂ nanosheets, which is conducive to rapid electron transport during the HER process. Significantly, the as-synthesized rGO/WS₂ nanosheets exhibit improved HER activity as compared to the undecorated ones. It needs a low overpotential of only 229 mV vs. RHE to afford a current density of 10 mA cm⁻². We believe that this hybrid structure demonstrated remarkable HER activity brought about by a compatible synergism between rGO and WS₂.