Enhanced Charge Separation of α-Bi2O3-BiOI Hollow Nanotube for Photodegradation Antibiotic Under Visible Light

It is highly desirable to exploit semiconductor materials with high photocatalytic degradation activity, especially bismuth oxyhalide semiconductor photocatalysts with special layered structure and suitable bandgap width. The low utilization rate of visible light and high recombination rate of photogenerated electron-hole of BiOI photocatalyst severely restrict its development. Herein, a heterojunction photocatalyst of α-Bi2O3-BiOI hollow nanotube was prepared by electrospinning method, solvothermal method and ion-exchange method. The α-Bi2O3-BiOI(BB-4, the stirring time of Bi2O3 in KI solution was 4 h) exhibited the best photocatalytic performance towards degrading the tetracycline hydrochloride(TC) solution, which could remove 85% of TC(10 mg/L) in 2 h under visible light irradiation. The estimated kTC of α-Bi2O3-BiOI(BB-4) was ca. 3.9 and 1.8 times as much as that of α-Bi2O3 and pure BiOI, respectively. It indicated that the formation of α-Bi2O3-BiOI heterojunction can significantly improve the separation efficiency of photogenerated electron-hole pairs, therefore the photocatalytic ability was enhanced. Furthermore, a corresponding photocatalytic mechanism was proposed that ·O2− radical and holes are the main active components in the photodegradation through trapping experiment.