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

Abstract

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.