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

摘要

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 H-2 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 H-2 production due to their extraordinary number of active edge sites with superior electrical conductivity. In addition, the observed H-2 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 H-2 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.