Preparation of nanostructured CeCO3OH particles from aqueous solutions and gels containing biological polymers and their thermal conversion to CeO2

Abstract

Nanostructured CeCO₃OH particles were prepared from aqueous solutions and gels containing CeCl₃ and biological polymers (gelatin and agar) by the addition of (NH₄)₂CO₃ solutions. The morphologies of the CeCO₃OH products depended on the kind and concentration of the biological polymers. Sheaf- and cocoon-like CeCO₃OH particles of ca. 2 μm in size consisting of fine particles of ca.10 nm in diameter were obtained from the precursor solutions containing gelatin. On the other hand, CeCO₃OH precipitates with inhomogeneous size and shape were obtained from the precursor solutions and gels containing agar. Such morphological variation of CeCO₃OH particles was thought to be due to the suppression of nucleation and growth of CeCO₃OH crystals by the biological polymers. The CeCO₃OH particles thus obtained were converted to CeO₂ particles by the heat treatment at 600 °C, and the morphology as well as nanostructure remained during the heat treatment.