Synthesis And Gas Adsorption Performance Of Highly Stable Zr-based Metal-organic Frameworks

Among the large family of metal–organic frameworks(MOFs), Zr-based MOFs, which exhibit rich structure types, outstanding stability, intriguing properties and functions, are foreseen as one of the most promising MOF materials. Although this specific type of MOFs is still in its early stage of development, significant progress has been made in recent years. Moreover, Zr-MOFs have a wide range of applications in catalysis, molecular adsorption and separation, drug delivery as well as fluorescent sensor. In respect of Zr-MOFs construction, a variety of MOFs with rich structures could be obtained by the coordination between different ligands and secondary building units to meet specific application requirements.In this thesis, three types of carboxylate ligands have been selected and used to react with Zr Cl4. Three Zr-MOFs with different structures have been successfully prepared and structureally charicterized. And then the gas adsorption performances of these MOFs have been investigated. Corresponding results are briefly described as follows:In the first part, the design and synthesis, structure, and applications of Zr-MOFs have been reviewed.The second part mainly includes two aspects.(1) Two different olefine acid ligands 4-carboxycinnamic acid(H2CCA) and 1,4-phenylenediacrylic acid(H2PDA) have been designed and synthesized. Two Zr-MOFs: Zr6(μ3-O)4(μ3-OH)4(CCA)6(BUT-220), Zr6(μ3-O)4(μ3-OH)4(PDA)6(BUT-221) based on the two ligands have been obtained and characterized by PXRD, IR, TGA, N2 adsorption-desorption. And then, the gas adsorption performances of BUT-220 and BUT-221 were studied. Single crystal diffraction analysis data show that BUT-220 and BUT-221 both have a three-dimentional(3D) microporous structure with the fcu topology. Through the gas adsorption study, it was found that BUT-220 and BUT-221 have good CO2 adsorption uptake and separation selectivities over N2, which demonstrates its potential application in CO2 capture and seperation.(2) A two-dimensional Zr-MOF, Zr6(μ3-O)8(H2O)8(SDC)4(BUT-222) with angular ligand 4,4’-sulfonyldibenzoic acid(H2SDC) has been successfully prepared and characterized by PXRD, IR, TGA, N2 adsorption-desorption. It was found that BUT-222 has good CO2 and H2 adsorption uptake and separation selectivities over CH4, demonstrating its potential application in CO2 removal for biogas purification.