K Intercalation-Assisted Co-Doped MoS₂ Nanoflowers for an Efficient Hydrogen Evolution Reaction

2D transition metal disulfides have emerged as promising Pt-alternative electrocatalysts for hydrogen generation. However, the sluggish water dissociation kinetics and limited active sites hinder their performance in alkaline media. Herein, we propose a two-step hydrothermal method to synthesize K intercalation-assisted Co-doped MoS₂ nanoflowers. These nanoflowers exhibit an overpotential of only 67 mV at a current density of 10 mA cm^-2, which exceeds that of pristine MoS₂ (143 mV). We demonstrated that the intercalation of K enlarges the interlayer spacing of MoS₂ nanosheets and facilitates the doping of Co. The incorporation of Co effectively improves the surface charge transfer efficiency of MoS₂ and accelerates water splitting with an energy barrier of 0.12 eV. This work offers an approach to activate the inert MoS₂ basal plane by chemical intercalation and atomic doping coengineering. It can be extended to develop other functional materials beyond water splitting.