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.