| Metal-organic frames(MOFs)are crystal structures with permanent holes formed by combining metal ions or clusters with organic ligands through strong bonds.A variety of MOFs structures can be obtained by flexibly matching metal ions or clusters with organic ligands in an appropriate way.MOFs have many advantages,such as structural diversity,adjustable pore structures,large specific surface area and coordination-unsaturated metal active centers.In recent years,researchers have paid an increasing attention to the research of using MOFs as precursor to prepare derivative materials.At present,a series of derivative materials,such as metal oxides(MOs),porous carbon(PC),MO-PC composites and metal-organic gels(MOGs),have been successfully produced with MOFs material as sacrificial templates.Inheriting the precursor's large specific surface area,permanent pore structures and good crystallization and other outstanding characteristics,MOFs-derived materials have shown tremendous potential applications in the fields of gas separation and adsorption,catalysis,energy storage and so on,thus further promoting the development of MOFs in the design and application of nanostructured materials.However,there are still many problems and challenges.For example,the processes of preparing MOFs precursor are often very complex and time-consuming.Improving the production efficiency without affecting the structure and performance of the products is very difficult.The preparation of MOFs-derived materials usually requires high-temperature thermal treatment,in which the original structures are often destroyed.The morphologies and structures of the synthetic products are usually out of control.Aiming at the above-mentioned problems,this dissertation synthesized a series of MIL-MOFs composites with novel structures and morphologies,through several methods,such as simple and high-efficient gelation method,controllable layer by layer self-assembly method and one-step method combined with element-doping.Based on these MOFs composites,MOFs-derived materials were obtained by proper thermal treatments.Researches about the design and application of these MOFs composites and their derived materials were conducted.The main contents of this dissertation are as follows:1.A highly efficient metal-organic gels(MOGs)drug delivery carrier,i.e.,MIL-100(A1)gels,has been fabricated by a facile,low-cost and environment-friendly one-not orocess.The unique structure of MIL-100(Al)gels leads to a high loading efficiency(620 mg g-1)towards doxorubicin hydrochloride(DOX)as a kind of anticancer drugs.DOX-loaded MOGs exhibited high stability under physiological conditions and sustained release capacity of DOX for up to 3 days(under acidic environments).They further showed sustained drug release behavior and excellent antitumor effects on in vitro experiments on HeLa cells,in contrast with the extremely low biotoxicity of MOGs.This work provides a promising way for the anticancer therapy,by utilizing this MOGs-based drug delivery system,as an efficient and safe vehicle.2.The Al2O3-porous carbon composites(MOGC)were obtained by using Al-based metal-organic gels as both metal source and carbon source.This realizes the effective combination of Al2O3 and porous carbon materials,the most popular two adsorbents for arsenic removal from water.The obtained MOGC has a high specific surface area(2477 m2 g-1)and pore volume(1.17 cm3 g-1).Then the ability to remove As(V)from aqueous solution as an adsorbent of MOGC was studied.The results show that MOGC has a high adsorption capacity(91.74 mg g-1)and a fast adsorption rate for As(V)(When the initial concentration of As(V)was 35 ppm,the pseudo-second-order adsorption kinetic model constant k2 reached 0.0147 g mg-1 min-1).This work has developed a new inorganic pollutant adsorbent with simple,clean and high-efficient synthesis process,which exhibits great potential application in the field of removing inorganic pollutants from water.3.In order to tackle the limitations for the practical application of Fe2O3 as the anode material in lithium ion batteries,such as drastic capacity falloff,short cyclic life and huge volume change during charge/discharge process.Carbon-coated Fe2O3(Fe2O3@MOFC)composites with a hollow sea urchin nanostructure were prepared by an effective and controllable morphology-inherited strategy.Metal-organic frameworks(MOFs)-coated FeOOH(FeOOH@MIL-100(Fe))was employed as the precursor and self-sacrificial template.During annealing process,the outer MOF layer protected the structure of Fe2O3 inside from collapsing,and will be converted to carbon coating layer in situ.When adopted as anode materials in LIBs,Fe2O3@MOFC composites showed an initial discharge capacity of 1810 mAh g-1 and a capacity preservation of 1577 mAh g-1 after 200 cycles at a current density of 0.1 A g-1.When increasing current density to 1 A g-1,a reversible and high capacity of 1171 mAh g-1 was obtained.The enhanced electrochemical performance was attributed to the MOFs-derived carbon coating layers and the unique hollow sea urchin nanostructures.They mitigated the effects of volume expansion,increased lithium-ion mobility of electrode,and stabilized the as-formed SEI films.4.Hierarchical sphere-structured Co-MOF and Co-MOF with three kinds of Fe-doping ratios(Fe/CoMOF-1,Fe/CoMOF-2 and Fe/CoMOF-3)were synthesized by one-step method.The porous nanoflower-structured derived composites were obtained by thermal treatment with four materials as precursors(Co3O4/C-1,Co3O4/C-2,Co3O4/C-3 and Co3O4/C-4).The lithium storage properties of these derived composites were studied when they were used as anode materials for lithium ion batteries.The experiments showed that the four composites all have excellent lithium storage properties.Among these composites,Co3O4/C-2 exhibited the best cycling performance and rate performance(the specific capacity tends to be stable at 1495.4 mAh g-1 after a short increase,and keeps steady in 200 cycles).The superior anode performance makes Fe-doped Co3O4/C a promising anode material for the next-generation high performance lithium-ion batteries. |
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