Tunable Synthesis of Polyhedron Bismuth Ferrite Particles via Hydrothermal Route

Bismuth ferrite (BiFeO3) powders were hydrothermally synthesized by using Bi(NO)3•5H2O and Fe(NO)3•9H2O as starting materials, and KOH used as a mineralizer. The large-scale polyhedral BiFeO3 particles were obtained by controlling KOH concentration, heating and cooling rate. It was found that the large-scale polyhedral BiFeO3 particles were synthesized favorably at the high KOH concentrations and an appropriate cooling rate was an important factor for synthesis of high crystallinity BiFeO3 particles. The quasi-cubic and truncated cubic particles of high crystallinity were obtained at the KOH concentration of 6 and 8 mol/L with the cooling rate of 0.2℃/min, respectively. The rough cubo-octahedron, truncated octahedron particles were obtained by changing the cooling rate to 0.1℃/min. The rough truncated cubic particles with pores were obtained by changing the cooling rate to 2℃/min. Morphologies evo- lution of large-scale polyhedron bismuth ferrite particles were observed by scanning electron microscope. The forma- tion mechanism of the regular morphologies was also discussed.