Controlled Fabrication of BiFeO 3 Uniform Microcrystals and Their Magnetic and Photocatalytic Behaviors

Bismuth ferrite (BiFeO 3 ) uniform microcrystals with various morphologies (microspheres and micro/submirocubes) were successfully synthesized by a controlled hydrothermal method. The resulting microstructures were characterized using X-ray diffraction, scanning/transmission electron microscopies and Raman spectroscopy. Possible formation mechanism for BiFeO 3 microcrystals was proposed. UV−vis spectra showed that the optical properties of the microsized BiFeO 3 crystals were strongly related to their shape and size. We further demonstrated the useful photocatalytic activity of these regular-shaped structures as determined by degradation of Congo red under visible-light irradiation (λ > 400 nm). Additionally, magnetic responses were observed to be influenced by the morphology of as-synthesized BiFeO 3 products, and the ferroelectric performance of BiFeO 3 submicrocube was also studied by piezoelectric force microscopy (PFM). Being a multiferroic semiconductor with suitable narrow band gap (∼2.2 eV) and uniform morphologies, these BiFeO 3 microcrystals might be useful for the design of devices combining magnetic, electronic, and optical functionalities.