Praperation Of Iron-Based Metal Organic Framework NH₂-MIL-101/MIL-101（Fe^Ⅱ） And The Catalytic Applications

In the last decades,bisphenol A have received much attention due to their persistence,potential bioaccumulation,and potential toxicity to humans.There is no doubt that bisphenol A can have a serious impact on global ecosystems.Therefore,there is a need to develop a simple,safe and sustainable method to remove bisphenol A from water bodies.multiphase Fenton like technology has proven to be a more effective method to eliminate bisphenol A due to its simplicity of operation,easy availability of raw materials and low energy consumption.As novel nanoporous materials,iron-based metal organic frameworks（Fe-MOFs）show great potential for multiphase Fenton-like oxidation.However,they also suffer from disadvantages such as excessive accumulation of Fe（III）,low·OH production efficiency,solution acidity limitation and so on.Thus,it is necessary for their modification.In addition,catalytically active Fe-MOFs can be used as peroxidase-like enzymes for H₂O₂ colorimetric sensing assays.In this thesis,efficient NH₂-MIL-101 and MIL-101（Fe^Ⅱ）catalysts are designed by regulating the valence composition of iron for the degradation of bisphenol A and the determination of H₂O₂,respectively.The main studies are as follows:Part I:Room temperature synthesis of NH₂-MIL-101 for Catalytic the degradation of bisphenol A and mechanistic study.The preparation of Fe-MOFs Fenton-like catalytic materials is usually faced with complicated operating procedure,high reaction temperature and the use of toxic solvents（e.g.hydrofluoric acid）.In this thesis,NH₂-MIL-101 Fenton-like catalytic material was successfully prepared by a one-pot hydrothermal method by a one-pot method at room temperature and without acid solvent.The effect of different amino amount doping on the structure of MIL-101 catalytic material and the catalytic degradation activity of bisphenol A were systematically investigated.The results showed that:NH₂-MIL-101 exhibits the best catalytic performance,could effectively catalyze the degradation of bisphenol A over a wide p H range,and shows good reusability and stability;The mechanism of the amino group for improving the catalytic performance of the material was further analyzed and verified by XPS characterization and Density functional theory（DFT）calculations.The presence of high valence iron usually leads to low catalytic activity of Fe-MOFs,and electron density is an important factor affecting the valence state of iron.In this chapter,the introduction of amino functional groups with strong electron supply ability increases the electron density of iron centres,thus enhancing the catalytic activity of Fe-MOFs;The possible mechanism of H2O2 activation was proposed by the analysis of the iron valence state of MOFs before and after the reaction,combined with quenching experiments.The introduction of amino groups not only induces the in situ generation of FeⅡin the framework structure,but also enhances the electrons transfer during the Fenton-like reaction,accelerating the Fe（III）→FeⅡhalf-reaction to some certain extent,which are conducive to promoting the decomposition of H2O2 to produce more ·OH.Part II: Colorimetric determination of H2O2 and glucose by MIL-101（FeII）and mechanistic study.In order to improve the stability and reduce the cost of natural enzymes,the design and development of low-cost and highly stable nanomaterial-based artificial enzymes has become a hot research field.In this paper,MIL-101（FeII）was prepared using the precursor substitution strategy（Fe2+ salt）and its peroxidase-like activity was investigated in detail.The results show that: In the presence of H2O2,MIL-101（FeII）can catalyze the substrate DPD to form pink oxidation product（ox DPD）,exhibiting excellent catalytic activity;Kinetic analysis shows that the affinity of MIL-101（FeII）towards both the substrate DPD and H2O2 are greater than that of horseradish peroxidase（HRP）;A reliable sensing platform for the rapid detection of hydrogen peroxide and glucose was established under optimised conditions with detection limits of 18.04 n M and 0.87 μM,respectively,allowing rapid determination of hydrogen peroxide and glucose over a wide linear range of 40-5000 n M and 0.6-300 μM,respectively,with detection limits as low as 18.04 n M and 0.87 μM.More importantly,the MIL-101（FeII）nanoenzyme can be successfully applied to the detection of hydrogen peroxide and glucose in real samples.