Preparation And Properties Of Zeolitic Imidazolate Frameworks-based Nanocomposite Materials

Zeolitic imidazolate frameworks（ZIFs）are a new subclass of metal-organic frameworks（MOFs）,which possess expanded zeolite topologies.ZIFs combine the advantages of zeolite and MOFs,and possese the characteristic of high thermal,chemical stability and tunable structure,etc.Guest@ZIFs composite materials are composed of an inner functional guest molecule（Guest）encapsulated inside of a ZIF,and have received concerning attention because of their applications in a variety of fields.In the second and third chapters of the paper,a series of Guest@ZIFs composite materials were designed and synthesized by using ZIF-8 and ZIF-67 as the frameworks encapsulated functional guest molecules.The exceptional porous structure makes ZIFs be an ideal precursor for construction of porous carbons.In the fourth chapter of the paper,four Co-based porous carbon materials were prepared by simple thermolysis of a Co-containing framework（ZIF-9）as the precursor in the inert gas at different temperatures.The dye adsorption performances of these porous carbon materials were evaluated.The main contents of this thesis are as follows:1.Three variable Rhodamine 6G（R6G）loaded ZIF-8 nanocomposites R6G@ZIF-8 were prepared by solvothermal method,and their luminescence properties were systematically studied.R6G@ZIF-8 nanocomposites exhibit intense luminescence with wide wavelength band at 560 nm and good stability in water environment.Luminescent detections of metal ions,anions,polyoxometalates and organic small molecules were fully studied by using the prepared R6G@ZIF-8fluorescence probe.Remarkably,the outcome of the luminescent detection indicates that R6G@ZIF-8 nanocomposites are capable of sensing of Fe³⁺,Cr（VI）-containing anions,several kinds of polymetallic oxygenate anions and aniline by fluorescence quenching with high sensitivity,low detection limit and high selectivity.More significantly,the R6G@ZIF-8 nanomaterials maintain high sensitivity and stability for repeated usage in Fe³⁺,Cr₂O₇^2-or aniline detection application after five times.The possible sensing mechanism for the luminescence quenching by the metal ions,Cr（VI）-containing anions and aniline have been further speculated by UV-vis absorption spectra.2.Three nanocomposites AQ@ZIF-67（EAQ=2-ethylanthraquinone;TBAQ=2-tert-butylanthraquinone）were designed and synthesized by one-pot strategy,using Co-based ZIF-67 and electrochemistry materials anthraquinone as the host framework and guest molecule,respectively.The electrochemical property of AQ@ZIF-67 was investigated.Cyclic voltammogram at AQ@ZIF-67 modified glassy carbon electrode（GCE）and carbon paste electrode（CPE）displayed the electrochemical properties of both ZIF-67 and AQ.Electrocatalysis property for H₂O₂ reduction was studied for AQ@ZIF-67 functionalized GCE and CPE by chronoamperometry（current-time plots）.The good sensitivities and stable amperometric responses for H₂O₂ reduction illustrate that AQ@ZIF-67 can be employed as a new type of electrochemical sensing materials for no enzyme detection of hydrogen peroxide.3.Four nanoporous carbon materials were synthesized by one-step calcination of Co-based ZIF-9 as precursor under a nitrogen flow at 600,700,800 and 900 ^oC,respectively.The structure and composition of as-synthesized nanoporous carbon materials were characterized and the results show that the micro-and meso-porous nanomaterials keep the structures of the precursor.Efficiently treat organic dyes from wastewater is an urgent environmental issue to be solved and a hot topic of research in recent years.Here,the adsorption performances of Z9-600 toward twelve common dyes,such as methylene green,malachite green,rhodamine B,rhodamine 6G,crystal violet,methyl blue,methyl orange,acid red 18 and acid orange 7 were systematically studied.The effects of ionic strength and temperature on the adsorption capacity have been studied,and the kinetic model has been discussed.Isolation,regeneration and reusability tests of exhausted Z9-600 to methylene green were also performed.The results elucidate that ZIF-9-based porous carbon materials possess excellent adsorption performance,easy separation and good recycling properties,and is a kind of emerging adsorption materials.