Herein, combining photocatalysis and Fenton oxidation, a photo-assisted Fenton system was conducted using Fe-doped Bi4O5Br2 as a highly efficient photocatalyst to realize the complete degradation of Tetracycline antibiotics under visible light. It has been observed that the optimized photocatalyst 5%Fe-doped Bi4O5Br2 exhibits a degradation efficiency of 100% for Tetracycline with H2O2 after 3 h visible-light irradiation, while a degradation percentage of 59.8% over the same photocatalyst and 46.6% over pure Bi4O5Br2 were obtained without the addition of H2O2 (non-Fenton process). It is unambiguous that a boost photo-assisted Fenton system for the degradation of Tetracycline has been established. Based on structural analysis, it demonstrated that the Fe atoms in place of the Bi sites may result in the distortion of the local structure, which induced the occurrence of the spontaneous polarization and thus enhanced the built-in electric field. The charge separation efficiency is enhanced, and the recombination of electrons and holes is inhabited so that more charges are generated to reach the surface of the photocatalyst and therefore improve the photocatalytic degradation efficiency. Moreover, more Fe (II) sites formed on the 5%Fe-Bi4O5Br2 photocatalyst and facilitated the activation of H2O2 to form oxidative species, which greatly enhanced the degradation efficiency of Tetracycline.
Keywords: Bi4O5Br2 nanosheet; carrier separation kinetics; element doping; photo-Fenton; tetracycline.