水热法制备二氧化铈纳米空心球及其吸附性能研究

Ceria Hollow Nanospheres Synthesized by Hydrothermal Method and Their Adsorption Capacity

用六水硝酸铈（Ce（NO_3）3·6H2O）作为铈源,以聚乙烯吡咯烷酮（PVP）为表面活性剂,在乙二醇的水溶液中通过水热法制备了单分散、粒径较均一的CeO2纳米空心球。利用傅立叶转换红外分析（FT-IR）、扫描电子显微镜（SEM）、透射电子显微镜（TEM）、X射线衍射（XRD）、X射线能谱（XPS）、N2等温吸附-解吸及紫外-可见光谱（UV-Vis）来表征CeO2纳米空心球并研究其吸附性能。结果表明,水热法制备的CeO2空心球是由立方萤石结构的纳米颗粒组装成的介孔中空材料,孔径分布窄,尺寸约为3-5 nm,空心球的直径约为400 nm,壁厚30 nm左右,空心球的BET比表面积为76.86 m^2·g^-1。讨论了CeO2空心球的制备机理,所制备的CeO2空心球对重铬酸钾溶液的吸附率可达到70%,约为CeO2粉末的3倍。

Uniform-sized and monodisperse ceria （CeO2） hollow nanospheres were synthesized in a ethylene glycol aqueous solution with cerium nitrate hexahydrate （Ce（NO3）3- 6H2O） as cerium sources and polyvinylpyrrolidone （PVP） as surfactant. The synthesized products were characterized by means of Fourier transform infrared spectroscopy （FTIR）, scanning electron microscope （SEM）, transmission electron microscope （TEM）, X-ray photoelectron spectrum （XPS）, X-ray diffraction （XRD）, N2 adsorption - desorption and UV-Vis. The results show that the porous CeO2 hollow nanospheres composed of small nanoparticles with cubic fluorite structure; the average diameter and wall thickness of the CeO2 hollow nanospheres were about 400nm and 30 nm respectively; they have a high specific surface area of 76.86 m^2g^-1 and BJH pore size about 3-5 nm. On the basis of time-dependent experiment, the relevant formation mechanism was proposed. The ceria hollow nanospheres show an excellent adsorption rate about 70% of heavy metal ions at room temperature for Cr（VI） solutions, which is 3 times higher than that of ceria powder.