The advancement of lithium-sulfur (Li-S) batteries is severely retarded by lithium polysulfides (LiPSs) shuttling behavior and sluggish redox kinetics. Herein, the heterogeneous composite with defective Bi₂Se_3−x nanosheets and porous nitrogen-doped carbon (Bi₂Se_3−x/NC) is prepared by selenizing bismuth metal-organic frameworks as a multifunctional sulfur host. The highly efficient immobilization-conversion on LiPSs is realized by the synergistic effect of structure construction strategy and defect engineering. It is found that Bi₂Se_3−x with the suitable amount of selenium vacancies achieves the best electrochemical performance due to the advantages of its structure and composition. These results confirm the intrinsic correlation between defects and catalysis, which are revealed by computational and experimental studies. Due to these superiorities, the developed sulfur electrodes exhibited admirable stability and a fairly lower capacity decay rate of approximately 0.0278% per cycle over 1,000 cycles at a 3 C rate. Even at the high sulfur loading of 6.2 mg·cm⁻², the cathode still demonstrates a high discharge capacity of 455 mAh·g⁻¹ at 1 C. This work may enlighten the development of mechanism investigation and design principles regarding sulfur catalysis toward high-performance Li-S batteries.

The basal planes of transition metal dichalcogenides are basically inert for catalysis due to the absence of adsorption and activation sites, which substantially limit their catalytic application. Herein, a facile strategy to activate the basal plane of WS₂ for hydrogen evolution reaction (HER) catalysis by phosphorous-induced electron density modulation is demonstrated. The optimized P doped WS₂ (P-WS₂) nanowires arrays deliver a low overpotential of 88 mV at 10 mA·cm⁻² with a Tafel slope of 62 mV·dec⁻¹ for HER, which is substantially better than the pristine counterpart. X-ray photoelectron spectroscopy confirms the surface electron densities of WS₂ have been availably manipulated by P doping. Moreover, density functional theory (DFT) studies further prove P doping can redistribute the density of states (DOS) around E_F, which endow the inert basal plane of P-WS₂ with edge-like catalytic activity toward hydrogen evolution catalysis. Our work offers a facile and effective approach to modulate the catalytic surface of WS₂ toward highly efficient HER catalysis.