Facile Synthesis of the Single-Atom Decorated Cox-MoS2/RGO Catalysts by Thermal-Annealing Vacancy-Filling Strategy for Highly Efficient Hydrogen Evolution

A “thermal-annealing vacancy-filling” synthesis strategy was developed to engineer cobalt single-atom catalysts (Co-MoS2/RGO) for exceptional hydrogen evolution reaction (HER) performance. By anchoring atomic Co onto Frenkel defect-engineered MoS2 nanosheets supported by reduced graphene oxide (RGO), we achieved simultaneous optimization of catalytic stability, electrical conductivity, and active site accessibility. The optimized Co3-MoS2/RGO hybrid demonstrates remarkable alkaline HER activity, requiring only 94.0 mV overpotential to achieve 10 mA cm−2 current density while maintaining excellent durability over extended operation. The atomically dispersed Co promoted HER kinetics through electronic structure modulation of MoS2 basal planes, creation of catalytic active centers, and defect-mediated synergies. The RGO further contributed to performance enhancement by preventing nanosheet aggregation, facilitating charge transfer, and exposing active sites. This defect engineering strategy provides a facile method for developing cost-effective, stable, and high-performance electrocatalysts for sustainable hydrogen production.