Optimization of Active Sites of MoS₂ Nanosheets Using Nonmetal Doping and Exfoliation into Few Layers on CdS Nanorods for Enhanced Photocatalytic Hydrogen Production

Transition metal dichalcogenides (TMDs) have emerged as promising nonprecious noble-metal-free catalysts for photocatalytic applications. Among TMDs, MoS₂ has been extensively studied as a cocatalyst due to its exceptional activity for photocatalytic hydrogen evolution. However, the catalytic activity of MoS₂ is triggered only by the active S atoms on its exposed edges, whereas the majority of S atoms present on the basal plane are catalytically inactive. Doping of foreign nonmetals into the MoS₂ system is an appealing approach for activation of the basal plane surface as an alternative for increasing the concentration of catalytically active sites. Herein, we report the development of earth-abundant, few-layered, boron-doped MoS₂ nanosheets decorated on CdS nanorods (FBMC) employing simple methods and their use for photocatalytic hydrogen evolution under solar irradiation, with lactic acid as a hole scavenger, under optimal conditions. The FBMC material exhibited a high rate of H₂ production (196 mmol·h^-1·g^-1). The presence of few-layered boron-doped MoS₂ (FBM) nanosheets on the surface of CdS nanorods effectively separated the photogenerated charge carriers and improved the surface shuttling properties for efficient H₂ production due to their extraordinary number of active edge sites with superior electrical conductivity. In addition, the observed H₂ evolution rate of FBMC was much higher than that for the individual few-layered MoS₂-assisted CdS (FMC) and bulk boron-doped MoS₂/CdS (BBMC) photocatalysts. To the best of our knowledge, this is the highest H₂ production rate achieved with MoS₂-based CdS photocatalysts for water splitting under solar irradiation. Considering its low cost and high efficiency, this system has great potential as a photocatalyst for use in various fields.