Preparation And Characterization Of Different Morphological Mesoporous ZrO₂ Derived From Zr-MOF

Metal organic frameworks?MOFs?, also known as the coordination polymer, a novel class of porous materials consisting of inorganic metal center?metal ions or metal clusters? coordinated to organic ligands?mostly of dicarboxylic acid or polybasic carboxylic acid and nitrogen-containing heterocyclic compounds? by self- assembly to formation of periodic network structure. The MOFs have diverse structural topologies and tunable functionalities. Therefore, most of the MOFs have lot of advantages, such as uniform pore size distribution, high specific surface area and chemical properties stability, which have attracted on considerable attention. Because of these advantages make it have important applications potential in gas storage and separation, heterogeneous catalysis, gas storage, gas sensing, biomedical and so on.In this work, a Zr-based MOFs with tetrahedral or octahedron structure were prepared using the benzene dicarboxylic acid as the organic ligand and transition metal ions Zr4+ as the metal precursor. The porous metal oxides with different sizes were synthesized by pyrolysis metal organic frameworks. The application of Zr--MOF and porous metal oxides was studied.The specific work is as follows:1. Using zirconium tetrachloride?ZrCl₄? as the metal ions source and terephthalic acid and [1,1'-biphenyl]-4,4'-dicarboxylic acid were selected as organic ligand, DMF as solvent, to synthesis of metal organic frameworks?UiO-66, UiO-67?. The crystal structure, specific surface area, pore size and thermal stability of UiO-66 and UiO-67 were characterized by many kinds of analysis methods,such as X-ray powder diffraction?XRD?, N₂ adsorption test, thermal gravimetric analysis?TG?. The results show UiO-66 and UiO-67 was successfully synthesized, and both have very high specific surface area and thermal stability.2. A black mesoporous material?mesoporous carbon-ZrO₂? was synthesized by pyrolysis of metal organic frameworks UiO-66 in nitrogen environment, and then pyrolysising the mesoporous carbon-ZrO₂ to get mesoporous ZrO₂ at different temperatures under oxygen atmosphere. Structure, morphology and porosity of the all products, were studied by X-ray powder diffraction?PXRD?, transmission electron microscopy?TEM?, thermal gravimetric?TG? and BET surface area method.The results of the study show that: mesoporous carbon-ZrO₂ treating with flow nitrogen environment have high surface area? 136m2/g?.3. The organic dye Congo red adsorption performance and adsorption efficiency were studied using mesoporous carbon-ZrO₂ as absorber. At room temperature, an amount of sample?60 mg? has a great adsorption effect on the Congo red?10 ml of 50 mg/L?, and the adsorption efficiency up to 99 % in 30 minutes. It was also found that the adsorption is very fast when using MCZ- flow N₂ as absorber. The 98% adsorption efficiency can be reached in 10 minutes.4. Proton conductive carrier imidazole was evaporate into nanochannels of UiO-67 at temperature of 120? in vacuum. The structure and properties of the hybridized materials were investigated by X-ray diffraction?PXRD?, transmission electron microscope?TEM?, electron energy spectrum?XPS? and thermal gravimetric analysis?TG?. Proton conductivity of hybridized materials was measured by ac impedance spectroscopy. The experimental results show that the hybridized materials is a new type of high-temperature anhydrous proton conducting materials, with the activation energy of 0.36 eV and proton conductivity of 1.44×10-3Scm-1 at 120?.