Preparation And Characterization Of Yttria Doped Zirconia Derived From The Metal- Organic Frameworks

Metal-organic frameworks(MOFs) are important class of porous materials. Its structure is mainly decided by inorganic metal ions and organic ligands. The MOFs has a complex spatial topological structure. The porous structure of MOFs can be design, control and decorate easily. In this work, we choose MOFs as templates, to obtain mesoporous metal oxides by using the method of pyrolysis. This is a relatively simple and economic method by selecting different structure and shape of the organic ligand and metal elements, designing synthesis with different topol ogical space structure and the secondary unit. The method of pyrolysis was used to remove organic coordination polymer chains, and metal ion was oxidized after inheriting the original space orderly structure. This is an orderly assembly and controllable synthesis of mesoporous metal oxides materials. Yttrium doped zirconia with high oxygen ionic conductivity and is widely applied in areas such as sensor, fuel cell electrolyte. In this thesis, yttrium doped zirconia with mesoporous structure was prepared using MOFs template:1. Through the solvent thermal method successfully synthesized a series of Y- Zr- MOFs material, which terephthalic acid as the organic ligand and the different proportion of Y/Zr atom as coordination elements. The structures and thermal stabilizations of the coordination polymers were characterized by many kinds of analysis methods, such as X-ray powder diffraction(XRPD), transmission electron microscope(TEM), thermogravimetric analysis(TG) methods.2. Through Two steps of the synthesis of Y- Zr- MOFs template, get different yttrium doped(Y/Z r molar ratio were 8%, 30%, 50%, 100%,) of the mesoporous zirconia. Application of X-ray powder diffraction, transmission electron microscopy(TEM), scanning electron microscope(SEM), X-ray photoelectron spectroscopy(XPS) and N2 absorpti on isotherm measurement methods for characterizing the mesoporous yttrium doped zirconium oxide. Studies show that the MOF template prepared yttrium doped zirconia is single polycrystalline phase materials, and has high specific surface area.3. By AC impedance spectroscopy method to measure the ionic conductivity of composite materials. The conductivity changing with the temperature and amount of yttrium doped and ion conductive mechanism was investigated. Research shows that the obtained yttrium doped zirconia has higher ionic conductivity.