Oxygen-vacancy-mediated photocatalytic degradation of tetracycline under weak visible-light irradiation over hierarchical Bi2MoO6@Bi2O3 core–shell fibers

Abstract

Novel oxygen-vacancy-rich hierarchical Bi₂MoO₆@Bi₂O₃ core–shell fibers were prepared by the in situ growth of Bi₂MoO₆ nanosheets on Bi₂O₃ nanofibers via an electrospinning–calcination–solvothermal method. The in situ growth contributed to the formation of an intimate interface between Bi₂MoO₆ nanosheets and Bi₂O₃ nanofibers, thereby constructing an efficient 1D/2D heterojunction and obtaining a 3D hierarchical structure at the same time. More importantly, the growth of Bi₂MoO₆ nanosheets on Bi₂O₃ yielded superficial oxygen vacancies. Such a special morphology and defect structure could not only increase the light harvesting, but also promote the separation of photo-induced electrons and holes through a Z-scheme charge transfer mechanism. Therefore, the Bi₂MoO₆@Bi₂O₃ composite photocatalyst showed excellent photocatalytic performance under weak visible-light illumination, thus exhibiting potential for application in the degradation of antibiotics. This promising Bi₂MoO₆@Bi₂O₃ photocatalyst had a superior photocatalytic degradation rate of 96.3% for TC under 5 W LED visible-light irradiation for 3 hours, which was 6.0 and 4.9 times higher than those of pristine Bi₂O₃ and Bi₂MoO₆, respectively. Moreover, two main possible photocatalytic degradation pathways for TC over the Bi₂MoO₆@Bi₂O₃ photocatalyst were also proposed.