The cantaloupe-like particles of CeOHCO_3 were synthesized in aqueous solution by using cetyltrimethylammonium bromide (CTAB) as soft template. Then, the bunchiness rods of CeO_2 were obtained by calcining CeOHCO_3 at 450 ℃. The results of thermogravimetric/differential thermal analysis reveal that an endothermic reaction with decomposition is involved in the transformation process from CeOHCO_3 to CeO_2. By scanning electron microscopy and X-ray diffraction analysis, it is found that the orthorhombic phase CeOHCO_3 particles are constituted of short nanorods with diameters ranging from several tens nm to over 100 nm, and the cubic phase CeO_2 rods are composed of small particles with diameter ca. 15 nm. From the results of UV-Vis absorption and photoluminescence analysis, it is found that the CeO_2 possess abundant defects, and the band gaps of the CeO_2 and CeOHCO_3 are ca. 2.70 eV and 3.87 eV, respectively.
