Amino Acid-assisted Systhesis Of Cerium Molybdate And Iron-cobalt Compound Nanostructures And Their Property Characterizations

In this thesis, cerium molybdate (Ce-Mo) nanostructures (such as the flowerlike, microspheric and bundlelike structure) were successfully synthesized via a facile route with the assistance of amino acid (lysine, Lys), the photocatalytic and adsorption performances of samples obtained were investigated. While the adsorption performance of cobalt ferrite (CoFe2O4) nanoparticles and nanospheres, which were tunably synthesized with the assistance of amino acid, was investigated using different organic dyes. Additionally, the Fe-Co LDHs precursors with different morphologies previously synthesized with the assistance of amino acid were calcined at different temperatures. The as-prepared samples were characterized by XRD, FT-IR, FESEM, TEM, TGA, XPS, BET and UV-vis. The major results were as follows:1. Ethylene glycol and deionized water were used as the solvents, amino acid as the surfactant, cerium molybdate (Ce-Mo) nanostructures were obtained through adjusting the reaction parameters. The results demonstrated that Lys molecules, as well as the volume ratio of mixture solvents, played crucial roles in the formation and growth of different nanostructures. Moreover, Ce-Mo nanostructures obtained exhibited excellent photocatalytic or adsorption performance on different dyes. The adsorption performance is mainly attributed to the electrostatic interaction between negatively charged polyoxometalate backbone and positively charged dye molecules. While the photocatalytic activity is probably attributed to oxidative species photogenerated by Ce+, resulting in the destruction of the chromophoric azo group (-N=N-), as well as the interaction between aromatic rings and polycyclic aromatic hydrocarbon in molecular structure.2. The adsorption performance of magnetic cobalt ferrite (CoFe2O4) nanostructures (nanoparticles and nanospheres), which were synthesized previously with the assistance of amino acid, was measured using different dyes. The results showed that the total adsorption efficiency of cobalt ferrite nanoparticles on rhodamine B was ca.98%, Moreover, cobalt ferrite nanoparticles on Methylene blue and Congo red was both ca.97%. The adsorption of anionic dyes by CoFe2O4nanostructures may be associated with their highly positively charged surface and the large specific surface area. These results suggest that CoFe2O4nanostructures with excellent adsorption performance could be potentially utilized as adsorbents for the removal of organic contaminants for environmental protection.3. Monodispersed Fe-Co LDH precursors with different morphologies (such as flowerlike and octahedral) were previously synthesized via a facile route with the assistance of amino acid (lysine, Lys), which were calcined at different temperatures from500℃to900℃. The products were characterized by XRD, FT-IR, SEM, TGA, and BET. The results indicated that the calcined temperature has an important influence on the morphology and crystallinity of the products. BET measurement showed that microporous and mesoporous structures were formed within all of the calcined products, and the pore sizes of the porous products were dependent on the calcined temperature.