Highly uniform Ce(OH)CO3 flowers were successfully prepared in large quantities using a facile hydrothermal approach from the reaction of Ce(NH4)(NO3)4 with CO(NH2)2 at 160 ℃ in a water-N 2H4 complex.The influences of the N2H4 content and temperature on flower formation were discussed.CeO2 flowers were prepared by thermal conversion of Ce(OH)CO3 flowers at 500℃ in air.Both Ce(OH)CO3 and CeO2 flowers were characterized by X-ray powder diffraction(XRD),and scanning electron microscopy(SEM).The UV-vis adsorption spectrum of the CeO2 flowers showed that the band gap energy(Eg) is 2.66 eV,which is lower than that of bulk ceria. Highly uniform Ce (OH) CO3 flowers were successfully prepared in large quantities using a facile hydrothermal approach from the reaction of Ce (NH4) (NO3) 4 with CO (NH2) 2 at 160 ° C in a water-N 2H4 complex. of the N2H4 content and temperature on the flower were formed. CeO2 flowers were prepared by thermal conversion of Ce (OH) CO3 flowers at 500 ° C in air. Both Ce (OH) CO3 and CeO2 flowers were characterized by X-ray powder diffraction XRD), and scanning electron microscopy (SEM). The UV-vis adsorption spectrum of the CeO2 flowers showed that the band gap energy (Eg) is 2.66 eV, which is lower than that of bulk ceria.