S-scheme WO_3-x/MoS₂ heterojunction photocatalysis coupling with micro-nano bubbles technology for enhanced antibacterial disinfection in water

This study developed an S-scheme WO_3-x/MoS₂ heterojunction photocatalytic system coupled with micro-nano bubbles (MNBs) for solar-powered water disinfection. The photogenerated carriers transfer in WO_3-x/MoS₂ followed an S-scheme route, accumulating photogenerated electrons at the conduction band (CB) of MoS₂ and holes at the valence band (VB) for robust oxygen and H₂O activation. More importantly, the disinfection performance of WO_3-x/MoS₂ was strongly dependent on the oxygen vacancy (OV) concentration in precursor WO_3-x. Consequently, WO_3-x/MoS₂ achieved 94.23 % inactivation of Escherichia coli (E. coli) and 93.09 % of Staphylococcus aureus (S. aureus) within 20 min under simulated solar irradiation. As expected, the introduction of MNBs significantly enhanced the disinfection efficiency by improving physical mass transfer, providing a sustained oxygen supply, and creating localized oxygen-enriched zones on the catalyst surface through electrostatic attraction. These combined effects broke the limitation of dissolved oxygen (DO) concentration, greatly amplifying reactive oxygen species (ROS) generation. Consequently, the system achieved 98.46 % inactivation of E. coli and 98.90 % of S. aureus within just 10 min. Mechanistic studies confirmed the synergistic action of photothermal conversion and ROS in antibacterial disinfection. This study provides valuable insights into the design of green and highly efficient antibacterial systems.