抄録
Nanostructured oxides of CeO2 and CeO2/TiO2 composite were prepared by surfactant-assisted mechanism. Metal alkoxides and laurylamine hydrochloride (LAHC) were used for synthesis of CeO2 and CeO2/TiO2 composite. Highly monodispersed and crystallized CeO2 nanoparticles of square shape were synthesized at low temperature, 353K, although formation of monodispersed cerium oxide nanoparticles was so far very difficult because of their highly aggregative properties in the aqueous reaction system. CeO2 nanoparticles were characterized by transmission electron microscope (TEM) images, selected area electron diffraction (SAED), and X-ray diffraction (XRD). XRD and SAED results showed that CeO2 nanoparticles had the cubic fluorite structure. Nanopaticles of CeO2 and CeO2/TiO2 composite oxide showed ability to oxidize I- to I2 without irradiation of light. This oxidation is attributed to the Lewis acid point. It was revealed that formation of Lewis acid point strongly depended on compositions of composite materials and conditions of calcination. The optimal conditions for production of Lewis acid points of the nanoparticles were found as at the mole ratio of cerium butoxide/TIPT = 75/25 and under the calcination temperature = 673K.
