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.