Improved Photo-Carrier Transfer by an Internal Electric Field in BiOBr/Nrich C3N5 3D/2D S-Scheme Heterojunction for Efficiently Photocatalytic Micropollutant Removal

Photocatalytic wastewater decontamination techniques hold eminent promise in mitigating environmental deterioration, yet the lack of distinctive photocatalysts prevents their further large-scale application. Herein, an S-scheme heterojunction photocatalyst BiOBr/C 3 N 5 (BBN) was fabricated for efficiently dislodging micropollutants under visible light. Among the BBN samples, the optimal BBN-2 demonstrated exceptional activity in photocatalytic TC removal with a rate constant of 0.0139 min ‒1 , which surpassed that of pure BiOBr and C 3 N 5 by 0.6 and 2.8 times, respectively. The spatially segregated photoredox sites and efficient photo-carrier separation propelled by an internal electric field are found to play a cardinal role in promoting photoreaction kinetics. Moreover, BBN-2 exhibited remarkable resistance to environmental interference and stability, retaining a high activity level after five runs. Through active radical detection, •O 2 ‒ , h + and •OH were identified as the primary active species in the photocatalytic reaction process. This research would encourage the exploration of C 3 N 5 -based photocatalysts for environmental protection. The well-designed BiOBr/N-rich C 3 N 5 3D/2D S-scheme heterojunction system enables efficient eradication of micropollutants in water under visible light, far bypassing pristine BiOBr and C 3 N 5 , respectively. This enhancement of photoactivity mainly originates from the simultaneous promotion of the generation and separation of photo-carriers induced by the optimization of optical response and establishment of an intense internal electric field.