High efficient ultraviolet photocatalytic activity of BiFeO3 nanoparticles synthesized by a chemical coprecipitation process

Single-crystalline BiFeO3 nanoparticles have been synthesized through a simple chemical coprecipitation process using bismuth and iron nitrates. By employing both X-ray diffraction and electron diffraction, the nanoparticles were unambiguously identified to have a rhombohedrally distorted perovskite structure. X-ray photoelectron spectroscopy investigation shows that Fe element exists as the Fe3+ valence state in the BiFeO3 nanoparticles. UV-Vis absorption spectrum indicates that the absorption cut-off wavelength of the nanoparticles is about 580 nm, corresponding to the energy bandgap of 2.10 eV. The BiFeO3 nanoparticles exhibited an efficient ultraviolet photocatalytic activity, more than 92% of methyl orange was decolorized after 260 min UV irradiation. Unexpectedly, the BiFeO3 nanoparticles do not show any efficient visible light photocatalytic activity, although the nanoparticles absorb visible light in the wavelength range of 400-580 nm.