Prepartion,Characterization And Properties Of Hierarchical UiO-66 And UiO-66-NH₂

Metal-organic frameworks?MOFs?are a novel category of porous materials comprised of ordered networks formed by transition metal cations and organic bridging ligands.The structure of a MOFs can be tailored by the judicious choice of metal-based building blocks and organic linkers with almost endless geometrical and chemical variations.Due to their diverse structure,adjustable functionality,and large surface areas,MOFs have shown potential applications in concern heterogeneous catalysis,gas storage,chemical sensing and drug delivery.However,most MOFs are microporous?pore size < 2 nm?.The small windows or pores exclude larger molecules from diffusing into the pores and thus limit their application in catalysis,drug molecule transformationand,and drug delivery.In this work,UiO-66 was used as starting materials to explore the method to prepare the hierarchically structural UiO-66.The results are as follows:?1?The synthesis of hierarchical UiO-66.Hierarchical UiO-66 materials were successfully synthesized just by adding a suitable amount of water into the conventional synthesis system of UiO-66 in the absence of any template or chelating agent.XRD,TG,NH3-TPD,SEM,N2-adsorption-desorption were employed to characterize the structural properties of final products.And the synthesized hierarchical UiO-66 materials show a better catalytic effect than the conventional UiO-66 in the esterification of n-hexylic acid and benzyl alcohol,indicating the advantages of the mesopores in the catalytic reactions involving bulky substrate molecules.In addition,the synthesized hierarchical UiO-66 materials exhibit good reusabilities.?2?The hierarchical UiO-66 was used as adsorbent to adsorb different dye molecules.The hierarchical UiO-66 samples show a better adsorptive property than UiO-66 sample in the aqueous solution of methyl orange and Rhdamine B,meaning superiority of the mesoporesin dye adsorption.Furthermore,the synthesized hierarchical UiO-66 materials show excellent reusabilities.?3?The preparation of hierarchical UiO-66-NH₂.The synthesis approach for hierarchical UiO-66 also can be adapted to amine functionalized UiO-66.The structural properties of the synthesized hierarchical UiO-66-NH₂ samples were characterized by XRD,TG,SEM,N2 adsorption-desorption and FTIR.The hierarchical UiO-66-NH₂ samples exhibit better catalytic activities than UiO-66-NH₂.