Crystallization behavior of nano-ceria powders by hydrothennal synthesis using a mixture of H2O2 and NH4OH

Homogeneous and well-crystallized nano-ceria (CeO2) powders were produced by hydrothermal synthesis using a mixture of H2O2 as the oxidizer and NH4OH as the mineralizer. The precipitates were prepared by mixture ligands of -OH and -OOH derived from NH4OH and H2O2. The hydrothermal synthesis was conducted at 200 degreesC for 6 h. The synthesized ceria powders were characterized as the crystalline phase identification by X-ray diffractometry, the chemical bonding by infrared spectrophotometer (FT-IR) and the morphology and particle size by transmission electron microscopy (TEM). Crystallization behavior of ceria powders using a mixture of oxidizer and mineralizer was more influenced by -OOH ligands than by -OH ligands to form Ce(OH)(x)(OOH)(4-x) as precursor with increasing concentrations of H2O2 with 10 - 20 times of the cerium(Ill) ion. In all samples, synthesized particle size was decreased with increasing concentration of oxidizer ranging from 6 to 12 nm in diameter. Morphology and size distribution of synthesized particles were relatively spherical and uniform, respectively. (C) 2003 Published by Elsevier B.V.