Hydrothermal Synthesis of BiFeO₃ Fine Particles

Abstract

Fine particles of BiFeO 3 were prepared from bismuth nitrate and iron nitrate in KOH solution by hydrothermal reaction. A single phase of BiFeO 3 was prepared under hydrothermal condition of K/Bi ≥ 120 and above 180 ºC. The TG curves of single phase of BiFeO 3 indicated that the products included a small amount of OH group or water in spite of no detection of potassium atom by EDX. The particle size of BiFeO 3 was ~ 10 µm and 10 ~ 20 µm for the products at 180 and 220 ºC, respectively. The particle prepared at 220 ºC was formed by aggregation of ~10 nm size particles with a cubic shape. From the pH dependence of ζ-potential the isoelectric point was about three.

Hydrothermal Synthesis and Crystal Structure of a Mixed-Valence Bismuthate, Na3Bi3O8

“…NaBiO 3 · n H 2 O is an attractive starting material for the hydrothermal synthesis of novel compounds − as well as hybrid composites for photocatalytic activities. − Its accurate crystal structure has not been solved. However, the crystal structure of the dehydrated phase, NaBiO 3 , was determined to be an ilmenite phase. , In 1955, Aurivillius expected a hexagonal unit cell for NaBiO 3 · n H 2 O from X-ray diffraction (XRD) data; however, no details for the crystal structure were reported.…”