Characterization of BiOBr/g-C3N4 heterostructures immobilized on flexible electrospun polyacrylonitrile nanofibers for photocatalytic applications

Numerous efforts have been devoted to improving the photocatalytic activity of g-C3N4 with BiOBr. However, most have used nano- and micro-sized structures that are arduous to be recycled, resulting in secondary pollution by the reaction system. BiOBr was grown on electrospun g-C3N4/polyacrylonitrile nanofibers (PAN NFs) by a solvothermal method. As a result, flexible heterojunction BiOBr/g-C3N4/PAN NFs were obtained. In addition, the coverage density and morphology of BiOBr on the surface of g-C3N4/PAN NFs can be tailored by altering the precursor concentration. BiOBr/g-C3N4/PAN NFs displayed enhanced photocatalytic activity of tetracycline hydrochloride (TCH) degradation under visible light irradiation. Notably, 3-BiOBr/g-C3N4/PAN NFs demonstrated the highest photocatalytic activity for TCH removal among the series of composite nanofibers, achieving 86% degradation efficiency within 1 h. A Z-scheme photocatalytic mechanism was rationally presented based on active species trapping experiments, the band energy potential, PL, and TPR analysis. The findings from the experiments suggested that the higher redox ability and charge separation efficiency were responsible for the enhancement. Lastly, the 3-BiOBr/g-C3N4/PAN NFs can recover quickly due to their self-supporting membrane structure. They also exhibited excellent durability over multiple consecutive cycles of the TCH photodegradation.