| 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 prepared MOFs exhibit tunable porosity, modifiable surface properties, large surface area, high thermal and hydrothermal stabilities which make MOFs a promise material in a wide range of applications, e.g., adsorption separation, biological medicine and catalysis. In this paper, a facile strategy for encapsulation of metal complex guests into MIL-100(Al) was proposed, and the host effects of MIL-100(Al) were investigated.In addition, a novel method for preparation of UiO-66 was explored. The physicochemical properties and catalytic performance of the UiO-66 sample prepared by this novel method were characterized. The main results are as follows:1) Preparation, characterization and catalytic properties of CuPhen/MIL-100(Al)A facile and efficient strategy for the encapsulation of a metal complex guest molecule into a MOF was proposed. This strategy involves pre-adsorbing metal salt on MOF, and then coordinating the metal ions with the organic ligand, as exemplified by encapsulation of tris(1,10-phenantroline) CuⅡ complexes (CuPhen) in MIL-100(Al) (denoted as CuPhen/MIL-100(Al)). The characterization results of XRD, SEM, DR UV-vis, ICP, N2 adsorption, as well as the catalytic performance in cycloalkane oxidation indicated that CuPhen were successfully encapsulated into the cages of MIL-100(Al) host by the proposed strategy. CuPhen encapsulated in MIL-100(Al) showed higher catalytic activity than the neat CuPhen and CuPhen encapsulated in zeolite-Y. The prepared CuPhen/MIL-100(Al) catalyst was stable and could be reused at least three times without significant loss in activity, and exhibited excellent shape-selective catalytic properties to the different substrates. Detailed investigation about the influence of reaction factors such as reaction temperature, reaction time, solvent and other factors on the catalytic performance over CuPhen/MIL-100(Al) was carried out. The optimum reaction conditions were as follows:0.05 g catalyst,10 mL solvent,9.5 mmol cyclohexane,38 mmol H2O2, 70℃,3h. This work is beneficial for the host-guest chemistry study and the development of new heterogeneous catalysts.2) Synthesis, characterization and catalytic properties of UiO-66 by vapor-phase transport methodUiO-66 was successfully synthesized in the absence of any amide solvents and hydrochloric acid by using the vapor-phase transport (VPT) method for the first time. The prepared UiO-66 (denoted as UiO-66-VPT) samples were characterized by XRD, SEM, FTIR, TGA and N2 adaorption. The results showed that the UiO-66-VPT sample has similar crystallinity and morpgology to the UiO-66 sample prepared by the conventional solvothermal method, but more linker deficiencies, indicating the presence of more exposed Zr defects in UiO-66-VPT. The prepared UiO-66-VPT exhibited higher catalytic activity, stability and reusability in the esterification reaction than the UiO-66 prepared by the conventional solvothermal method. This novel preparation method provides a new alternative method for the efficient and green synthesis of MOFs and modification of their properties. |
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