Three-dimensionally hierarchical MoS2/graphene architecture for high-performance hydrogen evolution reaction

Abstract

Molybdenum disulfide (MoS2) has been considered as a potential alternative to precious metal catalysts for the hydrogen evolution reaction (HER). However, the performance of MoS2 is still limited due to the poor electron conductivity, scarce active sites and low structural stability. A multiscale design of MoS2 in the structure and atomic composition is needed but still a great challenge. Herein, we report a well-organized three-dimensionally (3D) mesoporous hybrid structure of Co-doped MoS2 and graphene for highly efficient electrocatalytic HER. The mesoporous morphology ensures the well-dispersion of MoS2 layers and exposure of abundant edge sites. Doping of Co atoms into the MoS2 lattice improves the intrinsic HER activity of in-plane sulfur sites. The highly conductive and robust graphene network enhances the conduction of electrons and simultaneously improves the stability of the hybrid structure. The catalyst achieves a current density of 10 mA cm−2 at an overpotential of 143 mV versus the reversible hydrogen electrode (RHE) which is 200 mV lower compared with pure 2D MoS2, and maintains the activity for over 5000 cyclic voltammetry sweeps. This work provides a promising strategy for efficiently enhancing both the activity and stability of MoS2-based catalyst for HER.