Mn_xZn_1-xFe₂O₄ coated with β-Bi₂O₃ and β-MnO₂ as a highly efficient and magnetically recyclable photocatalyst for water treatment

ABSTRACT

Magnetic photocatalyst β-Bi₂O₃/β-MnO₂/Mn_xZn_1-xFe₂O₄ (BM/MZF) was successfully synthesised using dip-calcination method. The structure and properties of as-prepared samples were characterised by XRD, SEM, FT-IR, UV-DRS and VSM. The peaks of β-Bi₂O₃ and β-MnO₂ without an obvious change in the XRD pattern of BM/MZF confirmed that their morphology and phase stayed stable during the process of preparation. BM/MZF with a structure of bulked Mn_xZn_1-xFe₂O₄ coated with spherical and flaky β-Bi₂O₃ and spherical β-MnO₂ possesses good optional and magnetic abilities. The band gap of BM/MZF (2.34 eV) was less than that of β-Bi₂O₃ (2.48 eV) or β-Bi₂O₃/Mn_xZn_1-xFe₂O₄ (2.43 eV). Under visible light irradiation, the photodegradation rate of RhB using BM/MZF was 98.9% in 1.75 h, which was higher than that using β-Bi₂O₃ (48%) or β-Bi₂O₃/Mn_xZn_1-xFe₂O₄ (65%), and the photodegradation rate was still 95.7% after five cycles. The saturation magnetisation (Ms) of BM/MZF was 6.95 emu/g, and the average recovery rate was 87%.

KEYWORDS:

• β-Bi₂O₃/β-MnO₂/Mn_xZn_1-xFe₂O₄
• magnetic photocatalyst
• Mn_xZn_1-xFe₂O₄
• Rhodamine B

Acknowledgments

We would like to acknowledge the financial support from the Scientific and Technological Research Program of Chongqing Municipal Education Commission (Grant no. KJ1503107), State Key Laboratory of Coal Mine Disaster Dynamics and Control in Chongqing University (Grant no. 2011DA105287-MS201802).

Author Contributions

Conceptualization, T.W. and L.X.; Data Curation, T.W.; Formal Analysis, W.W., H.C. and X.W.; Investigation, Y.L., H.W. and Q.F.; Methodology, T.W.; Resources, L.X.; Supervision, C.L.; Writing—Original Draft, T.W.; Writing—Review and Editing, T.W. and L.X.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by the Scientific and Technological Research Program of Chongqing Municipal Education Commission [KJ1503107]; State Key Laboratory of Coal Mine Disaster Dynamics and Control [2011DA105287-MS201802].