Controllable Synthesis And Characterization Of Ceria Micro(Nano)Materials

Rare earth elements have unique4f electronic structure, the compounds have unique optical, electrical, magnetic properties and were regarded as a condicate of new materials. As an extremely useful rare earth oxide,ceria(CeO2) has a variety of applications, in the areas of functional ceramics, catalyst, gassensor, fuel cell, and uv-absorption has many market applications prospect. In recent years, the morphology and sizecontrol and performance application of CeO2nanomaterials, has become one of the most important research area. The main points of the dissertations are summarized as follows:With ammonium cerium nitrate as cerium source, urea as precipitant, sodium potassium tartrate as modifier, the Ce(OH)CO3micro(nano)meters dendrites were synthesized, which could convert to ceria dendrites through calcinations. The influence of the reactants concentrations, the dosage of additives and the reaction time on the morphologies of the products are carefully investigated, which result in the dendrites, nanorods, microspheres and a series of specific morphology of ceria crystals. Finally, based on the experiment fact, a growth model based on the surface lattice match and Ostward Ripeng process isproposed.By useing ceric sulfate and nickel sulfate as the starting materials, Ni-CeO2microcrystallites were synthesized under the conditions of hydrothermal. The influence of the dosage of reactants, the reaction time and the reactants temperature on the morphologies of the products are carefully investigated and a reasonable explanation is given. In the end, the electrochemical properties and adsorption properties of the typical composite structures are also investigated, which clearly shows that the photocatalytic performance of the product isgreatly enhance by the ceria microspheres.The selective preparation of lanthana micro(nano)structures has been realized by hydrothermal treating lanthanum nitrate. The influence of the reactant concentration, the amount of the precipitation agent and the kind of surfactant were discussed in detail. lanthana porous microspheres and polygon microcrystalline have been prepared respectively. Finally, lanthana polygon microcrystalline was investigated for photocatalytic degradation of methyl orange. The result shows that the performance of the product in photocatalytic degradation is greatly enhanced.