Synthesis of CeO_2 by thermal decomposition of oxalate and kinetics of thermal decomposition of precursor

摘要

CeO_2 was synthesized by calcining Ce_2(C_2O_4)_3?8H_2O above 673 K in air. The precursor and its calcined products were characterized using thermogravimetry and differential scanning calorimetry, Fourier transform infrared spectra, X-ray powder diffraction, scanning electron microscopy, and UV-Vis absorption spectroscopy. The result showed that cubic CeO_2 was obtained when the precursor was calcined above 673 K in air for 2 h. The UV-Vis absorption spectroscopy studies showed that superfine CeO_2 behaved as an excellent UVshielding material. The thermal decomposition of the precursor in air experienced two steps, which are: first, the dehydration of eight crystal water molecules, then the decomposition of Ce_2(C_2O_4)_3 into cubic CeO_2. The values of the activation energies associated with the thermal decomposition of Ce_2(C_2O_4)3?8H_2O were determined based on the Starink equation.