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

It is highly desirable to exploit semiconductor materials with high photocatalytic degradation activity,es-pecially 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 BiOl photo catalyst severely restrict its development.Herein,a heterojunction photocatalyst of a-Bi2O3-BiOI hollow nanotube was prepared by electrospinning method,solvothermal method and ion-exchange method.The a-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 irradia-tion.The estimated hrc of a-BiO-BiOI(BB-4)was ca.3.9 and 1.8 times as much as that of a-Bi2O3 and pure BiOI respectively.It indicated that the formation of a-BizO3-BiOl heterojunction can significantly improve the separatior efficiency of photogenerated electron-hole pairs,therefore the photocatalytic ability was enhanced.Furthermore,a corresponding photocatalytic mechanism was proposed that Oz radical and holes are the main active components in the photodegradation through trapping experiment.