Interface-engineered MoS2(1-x) Se2x Nanosheets on graphene for enhanced hydrogen evolution catalysis

Abstract

Hydrogen production via water electrolysis is a promising route toward sustainable and carbon-free energy. Transition metal dichalcogenide (TMD) nanosheets have emerged as efficient electrocatalysts for the hydrogen evolution reaction (HER), owing to their tuneable electronic properties and abundant active sites. In this study, we report the in-situ solvothermal synthesis of a compositionally tuneable library of molybdenum sulfoselenide (MoS_2(1-x)Se_2x) nanosheets uniformly anchored on reduced graphene oxide (rGO). The resulting MoS_2(1-x)Se_2x/rGO nanocomposites exhibit significantly enhanced HER activity, with the optimal MoS_0.6Se_1.4/rGO sample achieving a current density of 10 mA cm⁻² at a low overpotential of 118 mV and a Tafel slope of 46.6 mV dec⁻¹ in acidic media. The improved performance is attributed to the synergistic effects of sulfur and selenium incorporation, which modulate hydrogen adsorption energy, enhance orbital hybridization (Mo 4d, S 3p, Se 4p), and facilitate charge separation. Density functional theory (DFT) simulations further reveal that the Janus-type configuration enhances electronic conductivity and reactivity. The rGO substrate provides a conductive framework, promoting efficient charge transport and mechanical stability. These findings demonstrate that interface-engineered MoS_2(1-x)Se_2x/rGO hybrids are highly efficient and tunable HER catalysts, offering valuable insights for the design of advanced electrocatalytic materials.