Direct electrospinning preparation of Z-scheme mixed-crystal Bi2O3/g-C3N4 composite photocatalysts with enhanced visible-light photocatalytic activity

Abstract

A novel Z-scheme mixed-crystal Bi₂O₃/g-C₃N₄ composite photocatalyst was successfully prepared by a simple electrospinning–calcination approach. The micromorphology, configuration, chemical interaction and optical properties of the synthesized composite photocatalyst were analyzed and the photocatalytic degradation efficiency was estimated by the photodegradation of antibiotics. The results show that Bi₂O₃ nanofibers existing as α and β mixed-crystal phases are prepared and mixed with g-C₃N₄ nanosheets, thus forming a highly efficient α-Bi₂O₃/β-Bi₂O₃/g-C₃N₄ homoheterojunction. Transfer of the photogenerated electrons and holes in the fabricated α-Bi₂O₃/β-Bi₂O₃/g-C₃N₄ homoheterojunction follows a Z-scheme enhanced photocatalytic mechanism, resulting in the effective separation and transfer of photogenerated e⁻ and h⁺. Moreover, the mixed-crystal Bi₂O₃/g-C₃N₄ photocatalyst has an enhanced visible-light absorbance. Therefore, the Bi₂O₃/g-C₃N₄ composite displays high photocatalytic properties for degrading tetracycline hydrochloride under 5 W LED visible-light irradiation, and the high photocatalytic activity is maintained even after 5 cycles, indicating the outstanding stability and reusability of the composite photocatalyst.