Self-assembled growth of BiFeO3 meso-octahedral particles synthesized by a facile surfactant-free hydrothermal method

• Rhombohedral BFO octahedron was prepared by the surfactant-free hydrothermal method.
• EBSD was used to characterize the crystal orientation of meso-scale particles.
• The octahedral BiFeO3 was verified to be coated with (001)hex crystal plane.

Meso-scale BiFeO3 octahedral particles were synthesized by a hydrothermal method through modulating KOH concentration in the precursor solution. The morphologies of BiFeO3 particles were observed by scanning electron microscopy (SEM), displaying a morphological transformation from sphere to regular octahedron with the increase of KOH concentration. The time-dependent particle growth was also studied by SEM and the final products, octahedral BiFeO3 particles, were characterized by electron backscatter diffraction (EBSD) for understanding the crystalline growth. EBSD results show that the rhombohedral BiFeO3 octahedron is covered by eight crystal plane (001)hex, which is different from the previous report. The possible mechanism of crystal growth is discussed.