Rational construction of bromine doped rose-like Bi2O2CO3 microspheres for enhanced visible-light-driven degradation

Abstract

Optimizing the charge distribution of photocatalysts through halide ion doping has been recognized as an effective approach to enhance photocatalytic activity. Herein, the bromine doped rose-like Bi2O2CO3 microspheres were prepared through a one-step hydrothermal process. The visible diffuse reflectance spectroscopy (DRS) revealed that the bromine doping led to a narrowed band gap of Bi2O2CO3 and optimized band structure. In addition, bromine doping can achieve efficient separation of photogenerated electron-hole pairs. Thus, the photodegradation efficiency of the antibiotic oxytetracycline (OTC) and the dye rhodamine B (RhB) were significantly improved over bromine doped rose-like Bi2O2CO3 microspheres, which is 63.5% for OTC and 97.5% for RhB under visible light irradiation. The kinetic constants of the Br-Bi2O2CO3-2 material are 27.3 times for OTC and 156.2 times for RhB compared with those of pristine Bi2O2CO3. The enhanced photocatalytic performance can be attributed to the optimized carrier separation ability and broadened range of light response. The possible intermediates were identified by mass spectrometry (MS), and the degradation pathways were determined. A gradual decrease in toxicity during degradation was found by the Toxicity Estimation Software Tool (T.E.S.T). This work provides a new idea to construct high-performance photocatalysts for organic pollutants degradation.