Enhanced Photocatalytic Properties of All-Organic IDT-COOH/O–CN S-Scheme Heterojunctions Through π–π Interaction and Internal Electric Field

Herein, we present a distinct methodology for the in situ electrostatic assembly method for synthesizing a conjugated (IDT-COOH)/oxygen-doped g-C3N4 (O–CN) S-scheme heterojunction. The electron delocalization effect due to π–π interactions between O–CN and self-assembled IDT-COOH favors interfacial charge separation. The self-assembled IDT-COOH/O–CN exhibits a broadened visible absorption to generate more charge carriers. The internal electric field between the IDT-COOH and the O–CN interface provides a directional charge-transfer channel to increase the utilization of photoinduced charge carriers. Moreover, the active species (•O2–, h+, and 1O2) produced by IDT-COOH/O–CN under visible light play important roles in photocatalytic disinfection. The optimum 40% IDT-COOH/O–CN can kill 7-log of methicillin-resistant Staphylococcus aureus (MRSA) cells in 2 h and remove 88% tetracycline (TC) in 5 h, while O–CN only inactivates 1-log of MRSA cells and degrades 40% TC. This work contributes to a promising method to fabricate all-organic g-C3N4-based S-scheme heterojunction photocatalysts with a wide range of optical responses and enhanced exciton dissociation.