Study On Preparation And Functionalization Of Rare Earth Oxide Hollow Nanospheres

Inorganic hollow nanosphere, as a kind of functional materials, was widely studied inrecent years. It had low density, stable physical and chemical properties, such as largespecific surface area characteristics. Meanwhile, it had excellent optical, electrical ormagnetic properties, which could be used as catalysts, micro-reactor and drug deliverycarrier and so on. Rare earth oxide hollow spheres were more widely applied due to acombination of various properties such as optics, magnetism and electricity. Rare earthhollow nanospheres were prepared by using carbon spheres as template and theirfunctionalization were studied in this thesis. The technological conditions of Ceria oxide（CeO₂） hollow spheres had been studied by one-step hydrothermal method. Using carbonspheres as template, combining self-assembly and homogeneous precipitation method,CeO₂and Yttrium Oxide （Y₂O₃） hollow nanospheres were prepared, respectively. Theirproperties were studied preliminary. Moreover, the CeO₂hollow spheres were prepared byone-step hydrothermal method. The contents and results mainly as follows:1. With uniform sizes carbon microspheres had been successfully synthesized byhydrothermal method, utilizing glucose and deionized water as the source. A study of theoptimal technological conditions and the effect of the hydrothermal reaction temperaturesand time, raw material ratio, pH value and surface modification agent on the morphologyand structure of the obtained microsphere were conducted in this thesis. The resultsshowed that the carbon spheres at180℃,6h and pH9.0had better morphology. Thesurface of the spheres with size of150nm was hydrophilic. Add the urea while its massratio to glucose was1:5, uniform size carbon spheres, about10μm, were obtained whichwere well monodisperse, smooth surface.2. Using carbon spheres as template, CeO₂/carbon composite microspheres wereobtained by self-assembled with Cerium （Ⅲ） nitratehexahydrate precursor. Then CeO₂hollow nanospheres were obtained after calcined and final treatment. The form mechanismand photocatalytic property of CeO₂hollow spheres were analyzed. A study of the effect ofhexamethylenetetramine on the morphology and structure of hollow spheres was conducted. The results showed that the CeO₂hollow spheres had excellent decolorizingeffect for methyl orange solution. And the decolorization rate of the solution over94%when reacting6h.3. Using carbon spheres as template, Y₂O₃/carbon spheres composite microsphereswere prepared by ultrasonic dispersing technology and homogeneous precipitation method.Then Y₂O₃hollow nanospheres were obtained after calcined and final treatment. The formmechanism of Y₂O₃hollow spheres was analyzed. The influence of compositemicrospheres morphology on the dosage of PVP and the effect of hollow spheres crystalstructure on the calcination time were studied. The results showed that the spherical degreeand morphology of composite microspheres were improved when adding0.1g PVP. TheY₂O₃hollow nanospheres obtained were all pure cubic crystal system under700℃. Thecomposite was obtained when combined Y₂O₃powder and hollow nanospheres with butylrubber, respectively. The impact of stuffing, vulcanizing system, frequency andtemperature on the composite was studied. The results showed that the damping capacitywas best when nano-Y₂O₃was stuffing. And compared with Y₂O₃powder, the dampingcapacity of the composite was also better when adding Y₂O₃hollow spheres.4. The technological conditions of CeO₂hollow spheres had been explored byone-step hydrothermal method, utilizing Cerium （Ⅲ） nitratehexahydrate and ethyleneglycol as the source, as well as adding different acid and alkali reagents. Moreover, theinfluence of deionized water dosage, hydrothermal reaction time and different regents onthe morphology and structure of CeO₂hollow sphere were studied. The results showed thatCeO₂hollow sphere can be obtained by one-step hydrothermal method and the size washomogeneous about1μm. The impact of frequency on damping capacity of CeO₂/butylrubber composite was studied. Because of limited time, the technology of CeO₂hollowspheres for one-step hydrothermal method was immature and the research will be furtherexplored in the future.