Phase-modulated built-in electric field to boost photogenerated electron migration for efficient dehalogenation

Efficient halogenated antibiotic wastewater treatment can control the expression of antibiotic-resistant bacteria and genes and reduce environmental biotoxicity. Herein, a phase-modulated built-in electric field strategy was proposed to boost photogenerated electron migration and efficient utilization for dehalogenation. A 5 mV built-in electric field was constructed by modulating the crystalline phase of MoS2 (1 T/2H), resulting in a 3.62-fold increase in the photocurrent density compared to that of 2H-MoS2. Furthermore, the photocurrent density was further increased after introducing g-C3N4 by increasing the photogenerated electron injection volume. A high-efficiency electron migration tunnel (C-Npyridinic-Mo1T/2H) and two electron-rich active centers (Mo1T and Cg-C3N4) were formed to construct the high-efficiency photocatalysis-persulfate cooperative catalytic degradation system, as confirmed by density functional theory calculations. A 100% halogenated antibiotic degradation efficiency was achieved in<30 min, and the biotoxicity was significantly decreased after the reaction. The excellent detoxification performance and strong chain breaking and cleavage capabilities were derived from the phase-modulated built-in electric field structure and the 1 T/2H-MoS2@g-C3N4 activating persulfate system, respectively. The strategy utilized in this work provides a reliable method for controlling halogenated antibiotics via construction of a phase-modulated built-in electric field.