Nano-layer based 1T-rich MoS₂/g-C₃N₄ co-catalyst system for enhanced photocatalytic and photoelectrochemical activity

Photocatalytic disinfection based on semiconductors has been expected to tackle bio-contaminated water issue by leveraging reactive oxygen species (ROS) as “green” bactericide. However, semiconductor along usually inactivates bacteria tardily due to the fierce competition between high recombination rate of photo-excited charge carriers and the capture of them on surface to catalyse reactions. In this study, we in situ hybridized a cost-effective co-catalyst (MoS₂) on an earth-abundant semiconductor (g-C₃N₄ in nanosheets) based on similar nano-layered configuration. The spontaneously synthesized MoS₂ nano-layers (5–8 layers) was dominant in 1 T-phase which was found serviceable for efficient charge separation possibly by extracting electrons from g-C₃N₄ nanosheets through the fully contacted interface and accelerated charge transfer in highly conductive metallic MoS₂, meanwhile affording additional active sites both at edges and on basal plans relative to edge-active 2H MoS₂. The optimized 1 T-rich MoS₂/g-C₃N₄ nanocomposite impressively enlarged the photocurrent density by a factor of 5.5 compared to bare g-C₃N₄ and promoted the formation of H₂O₂ as the main ROS, thus leading to a better photocatalytic water disinfection performance than those of single component catalysts, 2H-rich counterpart and physical MoS₂/g-C₃N₄ mixture. This strategy would potentially enlighten the construction of other effective co-catalysts as alternatives to the expensive noble metals in catalysing photo-activated reactions.