Single-phase bismuth ferrite (BiFeO3) powders with different morphologies and sizes have been synthesized at 180 ℃ for 6 h with the assistance of PEG-4000 by hydrothermal method carefully. And the effect of PEG-4000 addition (0, 0.1, 0.2, 0.3 mmol) was studied on the morphology and size of BiFeO3 crystallites. The phase structure, morphology, absorption of BiFeO3 powders were characterized by using XRD, FT-IR, SEM and UV-Vis. The results show that adding suitable amount of PEG-4000 can effectively reduce the crystal size of BiFeO3 particles. When adding 0.1 mmol and 0.3 mmol PEG-4000, the single-phase perovskite structure BiFeO3 particles with regular morphology and smaller size can be obtained . The UV-Vis absorbance spectrum reveals that the absorption edges have a blueshift with decrease of the size of BiFeO3 particles. Furthermore, the photocatalytic activity of BiFeO3 powders was investigated by the degradation of methylene blue (MB). The experimental results indicate that they exhibit a pronounced photocatalytic activity for the MB decomposition. And with decrease in the particle size, the reactive activity can be enhanced.

PEG-4000; BiFeO3 particles; hydrothermal synthesis; photocatalysis