A ternary hybrid of Zn-doped MoS-RGO for highly effective electrocatalytic hydrogen evolution.

Modification of MoS-based catalysts is effective in solving the overdependence of hydrogen evolution reactions (HERs) on noble metal catalysts. In this work, a Zn-doped molybdenum disulfide-reduced graphene oxide (Zn-MoS-RGO) hybrid was synthesized in one step employing a hydrothermal method. By substituting the position of Mo, uniform doping with Zn improved the catalytic activity of MoS for HER. The interlayer spacing of MoS increased from 0.65 to 0.75 nm, demonstrating RGO effectively interpolate into MoS nanosheets. This prevented aggregation and exposed more edge active sites of MoS. According to density functional theory (DFT) calculations, the layered structure of the MoS nanosheets doped with Zn and intercalated with RGO promoted charge transfer and resulted in outstanding hydrogen evolution activity. Compared with MoS (6.86 eV), the Zn-MoS-RGO hybrid (5.47 eV) with a considerably lower energy level value exhibited excellent electrocatalytic performance. Under optimal conditions, at a potential of -0.3 V vs. RHE, the current density reached -169 mA cm in a 0.5 M HSO solution, 4.78 μmol of H was produced in 6 h, and the Faraday efficiency reached 92%. The results obtained herein indicated that Zn-MoS-RGO was a promising candidate for application in electrocatalytic HER.