Comparative study on photocatalytic material activity of BiOBr flower microspheres and sheet structure

BiOBr nanosheets and BiOBr flower-like microspheres were prepared by hydrothermal method and solvothermal method, respectively. On this basis, BiOBr nanosheets were modified by reducing agent reduction, preparing successfully Bi/BiOBr nanosheets. The XRD, SEM, UV-VisDRS, XPS and UV-vis spectrophotometry were used to characterize the morphological structures, physical properties and surface element composition of the photocatalysts. In addition, photocatalytic activity was analyzed by the ability to degrade the antibiotic norfloxacin. The results indicated that after irradiation of 500 W xenon lamp for 180 min, the degradation rates for norfloxacin of BiOBr nanosheets, BiOBr flower like microspheres, and Bi/BiOBr photocatalyst were 34.7%, 72.1%, and 97.2%, respectively. And the degradation of norfloxacin was in accordance with the first order kinetic model. Compared with BiOBr nanosheets, the other two samples have better visible light photocatalytic activity, of which the photocatalytic activity of Bi/BiOBr was the highest. And the half-life of norbofloxacin degraded by Bi/BiOBr was shortened to 25 min. In addition, The results of capture experiments indicated that the main active groups involved in the degradation reaction of norfloxacin by Bi/BiOBr photocatalysts under visible light conditions were $$ and h⁺. The reason why the activity of the Bi/BiOBr material photocatalyst increased is that the heterojunction formed by the wider bandgap BiOBr and the lower Fermi level Bi metal element effectively inhibits the recombination of holes and photogenerated electrons, which leads to the enhancement of oxidation capacity.