Molybdenum Disulfide Bilayers Hybridized With Reduced Graphene Oxide Nanosheets for Enhanced Hydrogen Evolution Reaction

ABSTRACT Two‐dimensional (2D) molybdenum disulfide (MoS 2 ) nanosheets have attracted attention as a promising and cost‐effective alternative catalyst for the hydrogen evolution reaction (HER). However, its aggregation and poor conductivity limit its catalytic activity. Consequently, researchers are exploring ways to improve the conductivity and density of electroactive edges of MoS 2 through hybridization with akin advanced 2D materials. Here, reduced graphene oxide (rGO) nanosheets are added to a liquid‐phase‐exfoliated MoS 2 dispersion to create drop‐casting hybrid MoS 2 @rGO electrodes for HER. The findings reveal the formation of 1.1 nm‐thick MoS 2 bilayers, with the catalytic performance of MoS 2 @rGO dependent on the degree of graphene oxide reduction. The rGO moderate reduction prevents the MoS 2 bilayers from restacking, improves conductivity, retains oxygenated groups that enhance interlayer spacing, and exposes more electroactive edges. When hybridized with rGO at an optimal reduction time, the resulting system outperforms pristine MoS 2 bilayers by attaining the overpotential of ca. 70 mV at 10 mA cm −2 along with a Tafel slope of ca. 46 mV dec −1 . This shows that MoS 2 bilayers hybridized with rGO offer a promising method for enhancing the electrocatalytic efficiency of MoS 2 ‐based electrodes, expanding opportunities for future strain and defect engineering, and high‐end twist‐angle assemblies for hybrid 2D‐material systems.