Study On Synthsis And Properties Of Nanomaterials Of Rare Earth Compounds Via Solution Route

In nanoscience, some interesting properties of material are related to the size and the surface morphologies, so it is important to design and delicately control the shape of nanocrystals. In recent years, nanomaterials of rare earth have stimulated much scientific and technological interest because of their promising applications in optical, electronic and magnetic properties. Chemical preparation of novel nanostructures and the investigation their general formation processes may be a solution to the precise control of their sizes, structures and properties. It is of great significance to tailor the property of materials in a controllable way by altering their structure, morphology, or composition. In this dissertation, based on new synthetic strategies and the new chemical solution method, systematic explorations have been carried out. We have synthesize a series of nano/micro-materials of lanthanide via a hydrothermal method successfully and realized the control of nanomaterails of rare earth. The main contents of this thesis are summarized as following:(1) Monodispersed YPO4·0.8H2O hexagonal nanoprisms have been synthesized using trisodium citrate (NaaCit) as the complexing agent by a facile hydrothermal route. The growth process of YPO4·0.8H2O hexagonal nanoprisms have been investigated. The shape and size of the as-prepared lanthanide phosphate can be turned effectively by controlling the reaction conditions, such as the molar ratio of complexing agent/Y3+, reaction temperature and time. To extend this method, other LnPO4·χH2O (Ln= Eu, Tb, Dy, Er) nanocrystals can also be achieved with different rare earth precursors. Further studies reveal that the morphology of the as-synthesized lanthanide phosphate is determined mainly by the interaction between rare earth ion and complexing agent. The experiments demonstrate that the complexing agent might play two main roles in the selective adsorption on the facets of hexagonal nanoprisms and kinetic control growth rates of these facets. In this paper, YPO4·0.8H2O nanoprisms could be doped by Eu3+through this simple hydrothermal route, and the photoluminescence properties of the obtained Eu3+:YPO4·0.8H2O nanomaterials were studied.(2) Based on the applications of the as-synthesized architectures by a complexing agent-assisted solution route, nearly monodisperse LnF3 (Ln=Y, La, Ce, Eu, Tb, Dy, Ho, Er) architectures with spindle-like, peanuts-like and nanoparticle shape have been synthesized on a large scale. The as-prepared architectures can be tuned effectively by controlling the reaction conditions, such as reaction time, the molar ratio of complexing agent/Y3+, the structure of the complexing agent and rare earth precurors.(3) CeO2 materials have attracted much attention because of their great potential applications in many fields. Nearly monodisperse CeO2 with hollow microspheres and nano octahedron shape have been synthesized by solvothermal routes. The main contents of solvothermal routes have been advanced, based on knowledge of nucleation and growth of nanoparticles. Studies have revealed that the morphology of the as-synthesized CeO2 is determined mainly by different reaction conditions, such as the concentration of CH3CH2OH in solution, the concentration of PVP in solution and reaction time. As a typical morphology, the growth process of monodisperse nanomaterials has been examined and the photoluminescence properties of the obtained Eu3+:CeO2 nanomaterials has been studied.