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.