P Dopants Triggered New Basal Plane Active Sites and Enlarged Interlayer Spacing in MoS₂ Nanosheets toward Electrocatalytic Hydrogen Evolution

MoS 2 -based transition-metal chalcogenides are considered as cost-effective, highly active, and stable materials with great potential in the application of electrocatalytic hydrogen production. However, their limited quantity of active sites and poor conductivity have hampered the efficiency of hydrogen production. Combining calculations and experiments, we demonstrate that P dopants could be the new active sites in the basal plane of MoS 2 and help improve the intrinsic electronic conductivity, leading to a significantly improved activity for hydrogen evolution. Furthermore, the P-doped MoS 2 nanosheets show enlarged interlayer spacing, facilitating hydrogen adsorption and release progress. Experimental results indicate that the P-doped MoS 2 nanosheets with enlarged interlayer spacing exhibit remarkable electrocatalytic activity and good long-term operational stability (with Tafel slope of 34 mV/dec and an extremely low overpotential of ∼43 mV at 10 mA/cm 2 ) . Our method demonstrated a facile technology for improving the electrocatalytic efficiency of MoS 2 for hydrogen evolution reaction through nonmetal doping, which could be explored to enhance and understand the catalytic properties of other transition-metal chalcogenides.