| Zirconia (ZrO2) based function and structural materials are one of the most important inorganic materials, and have been widely used in the fields of special ceramics, catalysts, oxygen monitor, fuel cell, chemistry industry and environmental protection. In the real applications, all of the ZrO2 concerned materials must undergoes the preparation of suitable raw powders. While, due to the huge surface energy of ZrO2, powders synthesized from the calcination processes possesses the agglomerated as well as the un-uniform products. The oxygen vacancy is one of the important structural units which provide the stability of the products, but this is not their only mechanism. Investigation methods on the oxygen vacancy and the effect of the vacancy on the structure, chemical and optical properties are the weak points and still keeping in vogue in the study of ZrO2.A series of methods avoiding calcination process while using aqueous system, namely hydro-thermal and solvothermal methods are adopted in this thesis to prepare pure ZrO2, Y2O3 doped ZrO2, Sm2O3 doped ZrO2, CeO2-ZrO2 solid solutions and nanopowders even mesoporous materials. Series of products with uniform structure and excellent performances are obtained. X-ray diffraction (XRD) in combination with Rietveld refinement, scanning electronic microscope (SEM), high-resolution transmission electronic microscope (HRTEM), X-ray energy spectrometer (EDS), Raman spectrometer (Raman), X-ray photoelectron spectrometer (XPS), ultraviolet to visible spectrometer (UV-vis), photoluminescence spectrometer (PL), differential scanning calorimeter/thermal gravimeter (DSC/TG), temperature programmed reduction (TPR), Fourier transformation infrared absorption spectroscopy (FTIR), in situ infrared diffusion spectroscopy (in situ IR) are used in the characterize of structure, morphology, composition, optical and redox properties of the samples. The effects of synthesis conditions on the performances of the products are carefully and intensively studied, some novel and advanced methods and techniques are used in the analyzing of affections and mechanisms of oxygen vacancy in the products. The following results are concluded:1. ZrO2 powders are prepared in acidic, basic and neutral circumstances, Y2O3 doped ZrO2 (YDZ) and Sm2O3 doped ZrO2 (SDZ) powders are prepared in basic circumstances using solvothermal method, respectively. All of the products are sub-micro sized non regular shaped particles agglomerated by nanoparticles with sizes of about 10nm. Pure ZrO2 powders obtained in acidic circumstance are dominated by monoclinic structures, while those from neutral circumstances are amorphous, and those obtained in basic circumstances are composed by the tetragonal and monoclinic structures. Uniform structured sub-stable t'-ZrO2 can be received using 4.0mol%Y2O3 dopant, while 8.0mol% Sm2O3 is needed if uniform structure should be concerned and fully stabilizing the cubic FSZ structures is received. The results should provide the guidelines to the concerned ceramic industries. Varies of violet to blue luminescent bands located in the range of 300nm-500nm are all observed and are ascribed to the bands originated from the energy levels built by F-center and the combined centers, while the intrinsic luminescence of rare earth cations are quenched. A configuration coordinate diagram containing an individual level built by the oxygen vacancy is proposed to interpreter the photoluminescence phenomenon of pure and doped ZrO2 materials, where the oxygen vacancy level can trap many kinds of the excited electrons and then followed by the transition and relaxation of the electrons and yield the observed PL bands. Large amounts of oxygen vacancies are formed in ZrO2 materials because of the +3 valence cations dopping, reduction and escaping of surface oxygen. The vacancy plays not only the role of stabilizing the cubic and tetragonal structures to room temperature, but also the origination of ionic reduction, luminescent center of violet-blue lights and quencher of intrinsic fluorescent for the rare earth cations.2. Series of CexZr1-xO2(x=0～1.0, CZ) powders with gradually changed compositions are prepared via solvothermal method, the products are composed of un-regular shaped agglomerates by nanocrystals with grain sizes of 10nm. The redox property, oxygen storage capacity (OSC) and repeatability of oxygen release were intensively studied. Structure of the products changed from mixture of two individual structures to uniform solid solutions when ceria compositions in the samples elevated gradually, the solubility of ZrO2 in CeO2 is calculated to be 33.12%. Fully repeatable oxygen absorption and desorption ability of the products were measured and the ability has not been diminished after three times of testing. The biggest oxygen release capacity was found to exist in the sample containing Zr:Ce=1:1, for which the OSC is measured to be 0.44 mol of O2/mol of Ce. The large OSC is analyzed to be originated from the gradual reduction of Ce4+and Zr4+. Even more, we report for the first time the meta-transition of CZ solid solution to pyroclore-Ⅱtype structures. The reason of the transition should be originated from the large percentage of Ce4+and Zr4+cations are reduced, many oxygen vacancies are formed on surface and inner part of the sample, and induced the lattice contraction according to the original one, resulting in the large OSC value measured in the experiments. In the process of reduction,-OH can be absorbed onto the surface in situ and the hydroxyls are used as the probe to monitor the formation of surface oxygen vacancies.-OH can be absorbed both onto O coordinated to Zr and onto O coordinated to Ce, but predominantly onto O connected to Ce in CZ solid solutions. In the repetitive reduction process, H2 predominantly coordinate with O connected to Ce, this result verified that the Ce4+is the key material in the oxygen storage concerned materials.3. Mesostructured ZrO2 and Ce0.5Zr0.5O2 solid solutions are prepared using three kinds of Gemini surfactants, CTAB and PI23 as the templates, and adapting hydrothermal, complexing-de-complexing process and evaporation induced self assembly (EISA) method. Mechanism of formation of mesostructures using Gemini and CTAB as the templates, redox property, OSC and oxygen release repeatability of the products are studied. Specific surface area of pure ZrO2 mesoporous materials is 151.9m2g-1, the luminescent bands is centered at 376nm. But structural collapse occurred in the calcination process and center of the PL bands red shift to 464nm. Intensity of the PL bands half diminished and all of the PL bands are ascribed to the relaxation of energy vacancy. Mesoporous products from hydrothermal and EISA method are dominated by secondary pores constructed by nanocrystals with sizes of about 15nm, but still containing some ordered channels, the maximum specific surface area is revealed to be 179.6 m2-g-1.Mesoporous materials from complexing-de-complexing process are highly ordered mesoporous materials. Redox ability of the M-CZ products are significantly promoted by the introduction of mesostructures, showing better uniformity of the solid solutions, higher oxygen storage ability, oxygen release repeatability and concentrated reduction range. The maximum OSC of the products is revealed to be 0.58 mol of O2/mol of Ce, and large part of the M-CZ products has the larger OSC values than the simple CZ solid solutions. Pore walls constructed by nanocrystals promoted the structural stability and the cubic phases of the products are kept unchanged even after reduction in H2 circumstance at 800℃for 2h. Oxygen vacancy in the M-CZ plays the roles of redox avenues and provides larger OSC.The aim of this thesis is preparation of ZrO2 based materials using aqueous methods and studying their properties, especially on the role and mechanism of oxygen vacancies in the typical materials. The method of preparing t'-phase YDZ and cubic SDZ powders using solvothermal method can provide a new avenue to the manufacturing of ceramic and functional devices and powder industries. The designed methods for evaluating the CZ catalysts can provide a new and practical technique in the concerned fields. The proposed configuration coordinate diagram for interpreting luminescence properties of ZrO2 based materials can serve as a new reference in the field. The invented novel complexing-de-complexing process to preparing high ordered mesoporous materials can be used in the synthesis of composite complex materials into mesoporous ones. The ZrO2 based materials obtained in this thesis can be used in such fields as high performance ceramics, automobile exhausts catalysis cleaning, the experiences and data collected in the experiments can provide the theoretical and technical supports in the manufacturing the concerned devices.
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