Nano Ceo <sub> 2 </ Sub> Liquid Preparation And Characterization

Nanocrystalline cerium(IV) oxide (CeO2) powders were prepared by means of different methods, Sol-Gel method, precipitation method and electrochemical method. The powders were analyzed by using X-ray diffraction(XRD) and Transmission electron micrograph(TEM). CeO2 powders in different ways were compared from shape of particles and preparation technics.Nanocrystalline CeO2 powders were prepared by sol-gel method using citric acid as complexation. From the experiment, the optimum preparation condition is as follows: Ce3~Vcitric =1:3, reaction temperature is 65癈, pH is 2-3, drying temperature of gel is 80 癈, sintering temperature is 500 癈 and sintering time is 2h. Crystal grows up in two steps. The activation energies of crystal growth were calculated to be 15.9kJ mol"1 and 148.7kJ mol"1 respectively.Cerous nitrate as originating material, ammonium hydrogen carbonate as precipitator, nanocrystalline CeC>2 powders were prepared by precipitation process. During the experiment, reacting solution was heated by microwave energy. The optimum preparation condition is as follows: reactant concentration is 0.25 ~0.3 mol-L"1, precipitator concentration is 0.2 ~ 0.4 mol-L'1, pH is 8~9, reacting temperature is 60~70癈, sintering temperature is 600癈.Nanocrystalline CeO2 were prepared by means of electrochemical method. The powders were analyzed by using XRD and TEM. Several factors, such as current density, reacting temperature and etc. were analyzed. The reacting mechanism of the formation of CeC>2 was discussed.The powders on different methods were compared form shape of particles, preparation technics. The features of every preparation method were introduced and its developmental trend was also predicted.