PREPARATION AND VISIBLE-LIGHT PHOTOCATALYTIC PROPERTIES OF BiFeO3 BY CO-PRECIPITATION METHOD

Abstract

In this study, nano BiFeO₃ powders were successfully synthesized by co-precipitation method which dissolved PVA in water with Bi/Fe/PVA = 1/1/3 molar ratio, at pH = 12. Research results showed that BiFeO₃ nano powders have been formed at a temperature of 110ºC after 4 hours of drying. When materials were calcined at higher temperatures, from 250ºC to 550ºC for 2 hours, BiFeO₃ appears more frequently, with a particle size of about 100nm. However, the material system had not achieved pure monophasic state, still had some other phases like Bi₂O₃, Bi₂₅FeO₄₀ and substrate. Differential thermal analysis method (TG/DTA), X-ray diffraction method (XRD), scanning electron microscopy method (SEM) were used to study the structural characteristics of materials. The study determined the effect of calcination temperature (250, 350, 450, 550ºC), pH values (1, 3, 6, 9, 12), presence of H₂O₂ on photocatalytic ability of the material formed in the treatment of RY160 in the visible light region. The dye concentration was determined by the method of  Ultraviolet – visible spectroscopy (UV-Vis) at 425 nm. Experimental results showed that, the RY160 degradation efficiency of BFO materials varied significantly when changing the pH and H₂O₂ was attended. The calcined materials were presented with high performance. Specifically, at pH = 3, added 1mL H₂O₂, the RY160 decomposing efficiency of BFO450 up to 100% after 90 minutes of lighting.