In situ construction of S-type core–shell NH2-MIL-125/TiO2 heterojunctions and mechanism for visible photodynamic antibacterial systems

Designing efficient visible light-driven photocatalytic antimicrobial agents presents significant challenges. In this study, S-shaped core–shell NH 2 -MIL-125/TiO 2 (NT-x) heterojunctions were constructed by simple in situ solvothermal method, as photocatalytic antimicrobial agents for efficient bactericidal use under visible light. Notably, 99.99% inhibition was achieved for both Escherichia coli and Staphylococcus aureus at low concentrations (0.02 and 0.035 mg mL −1 , respectively) after exposure to simulated sunlight for 20 min. Reasonable energy band configuration and built-in electric field of this structure provided improved photogenerated carrier transfer paths as well as enhanced separation and transport efficiency. Moreover, the core–shell structure enhanced the interaction between NH 2 -MIL-125 and TiO 2 , increased the total number of reactive sites, and promoted the efficient generation of reactive oxygen species. Finally, possible mechanisms for the inactivation of bacteria were discussed. This research offers new perspectives for the advancement of advanced metal–organic framework-based photocatalysts with antibacterial activity under visible light. Graphical abstract