In situ preparation of 3D flower sphere Bi4O5Br2/Bi24O31Br10 heterojunctions by calcination for enhanced antibiotic degradation

Abstract

The 3D flower sphere Bi 4 O 5 Br 2 /Bi 24 O 31 Br 10 was successfully prepared by solvothermal method and subsequent calcination. During the calcination process, Bi 4 O 5 Br 2 nanosheets polymerized gradually into Bi 24 O 31 Br 10 nanosheets with the construction of heterojunctions and the morphology changed obviously with the original dense flower sphere structure assembled by nanosheets gradually changing to loose structure accompanied by a slight volume reduction. The Bi 4 O 5 Br 2 /Bi 24 O 31 Br 10 heterojunction framed was successfully proved by XRD, HRTEM and XPS. In addition, the light absorption edge and photocurrent responses of synthesized heterojunction materials were significantly stronger than that of pure Bi 4 O 5 Br 2 and Bi 24 O 31 Br 10 . BOB-300 showed the highest photocatalytic performance compared with single Bi 4 O 5 Br 2 and Bi 24 O 31 Br 10 for the degradations of CIP and TC. Moreover, the contributions of ·O 2 − and h + were further studied, especially ·O 2 − played a primary role in the photocatalytic process. The photocatalytic mechanism and calcination reaction process for the Bi 4 O 5 Br 2 /Bi 24 O 31 Br 10 heterojunction were proposed. • The novel 3D flower sphere Bi 4 O 5 Br 2 /Bi 24 O 31 Br 10 was prepared by solvothermal method. • Bi 24 O 31 Br 10 can be obtained by calcining the intermolecular debromination of Bi 4 O 5 Br 2 . • Bi 4 O 5 Br 2 /Bi 24 O 31 Br 10 notably improved transfer of photogenerated electron-hole pairs. • Bi 4 O 5 Br 2 /Bi 24 O 31 Br 10 exhibited superiorly activity and stability for CIP degradation.