Growth behavior of nanosized ceria powders prepared by coprecipitation routes

Nanosized ceria (CeO2) powders were obtained by coprecipitation routes of cerium nitrate hexahydrate [Ce(NO3)3·6H2O]. The growth behavior of the nanosized CeO2 powders was investigated by X-ray diffraction, transmission electron microscopy and selected area electron diffraction. The XRD results showed that the dried precursor powders contained a single crystalline phase of CeO2, and only a single phase of CeO2 appeared when the dried precursor powders were calcined at different temperatures for various durations. Moreover, the crystallite size of CeO2 increased on increasing the calcination temperature and duration. The kinetics equation of the nanosized CeO2 powders grown between 673 and 1273 K for various durations is described asDt−D0=ktmexp(−56.42×103/RT) where k=7.5×10−1 and m=0.20 when t≤360 min and 673 K≤T≤873 K; k=8.46 and m=0.43 when 5 min≤t≤30 min and 1073 K≤T≤1273 K; and k=3.17×10 and m=0.03 when 30 min≤t≤360 min and 1073 K≤T≤1273 K.