High-Concentration Niobium-Substituted WS2 Basal Domains with Reconfigured Electronic Band Structure for Hydrogen Evolution Reaction

Extrinsically controlling the intrinsic activity and stability of two-dimensional (2D) semiconducting materials by substitutional doping is crucial for energy-related applications. However, an in situ transition-metal doping strategy for uniform and large-area chemical vapor deposited 2D semiconductors remains a formidable challenge. Here, we successfully synthesize highly uniform niobium-substituted tungsten disulfide (Nb-WS2) monolayers, with a doping concentration of nearly 7% and sizes reaching 100 itm, through a metal dopant precursor route, using salt-catalyzed chemical vapor deposition (CVD). Our results reveal unusual effects in the structural, optical, electronic, and electrocatalysis characteristics of the Nb-WS2 monolayer. The Nb dopants readily induce a band restructuring effect, providing the most active site with a hydrogen adsorption energy of 0.175 eV and hence greatly improving its hydrogen evolution activity . The combined advantages of the unusual physics and chemistry by in situ CVD doping technique open the possibility in designing 2D-material-based electronics and catalysts of novel functionalities.