Controlled Fabrication of BiFeO3 Uniform Microcrystals and Their Magnetic and Photocatalytic Behaviors

Bismuth ferrite (BiFeO3) uniform microcrystals with various morphologies (microspheres and micro/submicrocubes) 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 BiFeO3 microcrystals was proposed. UV-vis spectra showed that the optical properties of the microsized BiFeO3 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 (lambda > 400 nm). Additionally, magnetic responses were observed to be influenced by the morphology of as-synthesized BiFeO3 products, and the ferroelectric performance of BiFeO3 submicrocube was also Studied by piezoelectric force microscopy (PFM). Being a multiferroic semiconductor with suitable narrow band gap (similar to 2.2 eV) and uniform morphologies, these BiFeO3 microcrystals might be useful for the design of devices combining magnetic, electronic, and optical functionalities.