Microemulsion-Assisted Synthesis of Ag2CrO4@MIL-125(Ti)-NH2 Z-Scheme Heterojunction for Visible-Light Photocatalytic Inactivation of Bacteria

Metal-organic frameworks (MOFs) are new porous materials composed of metal centers and organic ligand bridges, which received great attention in the field of photocatalysis. In this work, Ag2CrO4@MIL-125(Ti)-NH2 (denoted as AgCr@M125) Z-scheme heterojunctions were synthesized via a simple microemulsion method, by which highly dispersed nano-sized Ag2CrO4 can be anchored uniformly on the surfaces of porous MIL-125(Ti)-NH2 (denoted as M125). Compared with pure M125 and Ag2CrO4, the as-prepared AgCr@M125 hybrids show significant photocatalytic efficiency against inactivated Staphylococcus aureus (S. aureus), reaching over 97% inactivation of the bacteria after 15 min of visible light irradiation. Notably, the photocatalytic activity of the obtained 20%AgCr@M125 is about 1.75 times higher than that of AgCr-M125, which was prepared via a traditional precipitation method. The enhanced photocatalytic antibacterial activity of the AgCr@M125 photocatalytic system is strongly ascribed to a direct Z-scheme mechanism, which can be carefully discussed based on energy band positions and time-dependent electron spin response (ESR) experiments. Our work highlights a simple way to enhance the antibacterial effect by coupling with Ag2CrO4 and M125 via a microemulsion-assisted strategy and affords an ideal example for developing MOFs-based Z-scheme photocatalysts with excellent photoactivity.