Study On Optical And Magnetic Properties Of Octahedron-like CeO₂ Nanoparticles Prepared By Hydrothermal Method

As one of important rare earth oxides. CeO2 has a broad application prospect in catalysis, fuel cells, sensors and magnetic materials, and other fields. In this dissertation, octahedron CeO2 nanoparticles have been synthesized by hydrothermal method using Ce(NO3)3·6H2O as the cerium source and Na3PO4·12H2O as precipitant. And Nd was further added to prepare samples. Their crystal structure, composition, morphology, optical properties and magnetic properties have been characterized by X-ray diffractometer, X-ray photoelectron spectrometer, scanning electron microscope, transmission electron microscope, ultraviolet-visible spectrophotometer, fluorescence spectrometer, laser confocal micro Raman spectrometer, and comprehensive physical measurement system. The main contents and results of the study are as follows:1. CeO2 nanoparticles samples are synthesized by hydrothermal method using Ce(NO3)3·6H2O as the cerium source and Na3PO4·12H2O as precipitant, respectively at 130,160,190,220 and 250℃ for 10 h. The results show that octahedral CeO2 nanoparticles have been synthesized at 190℃. Based on this work, octahedron Ce1 xNdxO2-θ (x=0.01,0.02,0.05,0.10) are further prepared by adding different proportions ofNd(NO3)3·6H7O.2. Particle size of octahedron CeO2 nanoparticles prepared at 190℃ for 10 h is 500-600 nm. In ultraviolet-visible spectra, it has higher absorbance for ultraviolet light than the samples prepared at other temperatures. The as-synthesized octahedron CeO2 nanoparticles have prominent fluorescence luminous performance. The ultraviolet absorbance of octahedron CeO2 nanoparticles doped Nd decreases and then increase with the increase of amount of Nd. Meanwhile fluorescence luminous intensity of octahedron CeO2 nanoparticles doped Nd enhances and then decreases with the increase of amount ofNd.3. Octahedron CeO2 nanoparticles synthesized at 190℃ for 10 h show paramagnetism at room temperature. However octahedron CeO2 nanoparticles synthesized at 250℃ for 10 h show room temperature ferromagnetism. Octahedron Ce0.95Nd0.05O2-θ nanoparticles doped Nd (x=0.05) also show ferromagnetism at room temperature.4. Compared with octahedral undoped CeO2 nanoparticles prepared by hydrothermal method at 190℃ for 2 h,5 h,10 h, and 20 h, it can be found that they have a single CeO2 lattice structure. With the increase of reaction time, the ultraviolet absorbance of the samples decreases to a certain extent, and their band gap changes which is related to the reaction time.