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

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 5W 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.