Synthesis of a BiOIO3/Bi2O4 heterojunction that can efficiently degrade rhodamine B and ciprofloxacin under visible light

In this paper, BiOIO 3 and Bi 2 O 4 nanosheet monomers were synthesized and used to prepare several BiOIO 3 /Bi 2 O 4 composites by an ultrasonic impregnation method. The resulting photocatalytic materials were characterized by XRD , SEM, TEM, XPS , FTIR, PL , UV–Visible diffuse reflectance spectroscopy (DRS), and BET. The photocatalytic activity of the BiOIO 3 /Bi 2 O 4 composites was evaluated by the degradation of rhodamine B (RhB) and ciprofloxacin (CIP) under simulated sunlight and compared to the activities of BiOIO 3 and Bi 2 O 4 operating alone. The results showed that Bi 2 O 4 was closely attached to the surface of BiOIO 3 , and the composite had a good degradation effect on RhB and CIP, with the best performing material being a 0.9-BiOIO 3 /Bi 2 O 4 composite, which achieved 97.6% degradation of RhB within 60 min and 85.6% degradation of CIP within 120 min. The observed degradation performance was considerably higher than that of other composite samples and monomers due to the good energy level matching of the BiOIO 3 /Bi 2 O 4 composite, which broadened the light response interval, improved the electron transfer rate and enhanced the photocatalytic activity. Free radical capture experiments showed that the ·O 2 - $\stackrel{-}{2}$ and h + free radicals significantly contributed to the degradation of pollutants. Cyclic tests showed that the composite also had good stability. The results of this study showed that bismuth-based photocatalysts might be used for environmental remediation.