NaOH-induced formation of 3D flower-sphere BiOBr/Bi_4O_5Br_2 with proper-oxygen vacancies via in-situ self-template phase transformation method for antibiotic photodegradation

摘要

In this study, a novel 3D flower-sphere BiOBr/Bi_4O_5Br_2 with proper-oxygen vacancies (OV) was successfully synthesized by using 3D BiOBr as a self-sacrificed template, NaOH as a structure-driving reagent and midwifery agent of OV. The synthesis mechanism was systematically studied. It revealed that Bi_4O_5Br_2 lamina generated via in-situ phase transfer tightly interspersed in the interior and surface of 3D BiOBr hierarchical structures; calcination temperature, stirring time and -OH concentration can optimize the composition and structure of materials. Also, the calcination conditions (temperatures and air or N_2 atmosphere) can regulate the OV's concentration. Ultimately, 3D hierarchical architectures, the optimal heterojunction composition and OV with proper concentrations three positive factors synergistically promoted the photoelectric activity of BiOBr/ Bi_4O_5Br_2-OV, making it exhibit ultrahigh photocatalytic activity for antibiotic photodegradation (tetracycline. TC; ciprofloxacin, CIP). We believe the synthesis methods and design idea mentioned in this paper have high instructive significance to prepare high-performance materials.