Activation of MoS2 via tungsten doping for efficient photocatalytic oxidation of gaseous mercury

Defect engineering and heterogeneous doping are considered as the effective routes to improve the photocatalytic activity of MoS2. In this study, tungsten was used to produce sulfur defects and tungsten doping on MoS2 by one step hydrothermal treatment. Tungsten doping not only promotes the formation of sulfur defects, but also accelerates the efficiency of separation and transfer of electron-hole pairs, which enables the samples to maintain high catalytic oxidation activity for a long time. Furthermore, comparative experiments show that sulfur defects can promote the activation of O2 and the formation of more active O2- and ·OH species. As a result, the W-doped MoS2 exhibited a high removal efficiency of more than 99% of gaseous mercury. In addition, W-doped MoS2 showed good stability, long term durability, enhanced water and sulfur resistance under light illumination. This work provides a novel direction for designing efficient photocatalysts based on transition metal dichalcogenides.