Synthesis And Application Of Ultrathin 2D Nanosheets Based On MOFs

Ultra-thin two-dimensional MOFs nanomaterials have become an emerging two-dimensional material due to their atomic thickness,regulatable structure and function,abundant active sites,large specific surface area and ordered porous structure.However,the application research of two-dimensional MOFs nanomaterials is still in the initial stage.The main constraints are:1)the establishment of simple and efficient preparation methods;2)the improvement of stability of solution and solid state;3)the exploration of the best application field.Based on the above research background,this paper has carried out a large number of simple and efficient preparation methods,physical and chemical properties research and application exploration based on the ultra-thin two-dimensional MOFs nanomaterials coordinated by polypyridyl bridged ligands and monodentate reactive groups.The specific content of the study is as follows:（1）A simple and efficient preparation method for ultra-thin two-dimensional MOFs nanomaterials were established:Four layered two-dimensional MOFs precursor bulk were systhesised{[Co（NCS）₂（pyz）₂]_n（pyz=pyrazine）;[Co（NCS）₂（4,4’-bpy）₂]_n（4,4’-bpy=4,4’-bipyridyl）;[Cu（NCS）₂（pyz）]_n and[Fe（NCS）₂（1,3’-bpp）₂]_n（1,3’-bpp=1,3-dipyridylpropane）},fully characterized its crystal structure and physical and chemical properties.On this basis,a top-down solvent-assisted ultrasonic stripping technique was utilized to prepare atomic-thick two-dimensional nanomaterials that were stable in solution and solid state.The structure of two-dimensional nanomaterials was fully characterized by thermogravimetric analysis,powder diffraction and infrared spectroscopy.The morphology,size and thickness of two-dimensional nanomaterials were investigated by transmission electron microscopy,atomic force microscopy and field emission scanning electron microscopy.（2）The physical and chemical properties of ultra-thin two-dimensional MOFs nanomaterials were studied.The optical properties of the above ultra-thin two-dimensional MOFs nanomaterials under 980 nm laser irradiation were studied.And the change in the optical properties of the 2D nanosuspension by various temperature was also investigated.Two-dimensional MOFs were prepared.A composite of two-dimensional MOFs nanosheets with dyes such as azobenzene and azopyridine was prepared,and the cis-trans isomerization of the composites was performed by different wavelengths of laser.The spin-crossing materials were stripped into ultra-thin two-dimensional nanometers.Changes in the magnetic properties of the material.（3）The application of ultra-thin two-dimensional MOFs nanomaterials were explored.The application potential of ultra-thin two-dimensional nanosheets[Co（NCS）₂（pyz）₂]_n that used in solvent visualization test strips was investigated,which need a smart phone called viewing app.An online visualized test strip for isomer recognition and quantitative and qualitative determination of the polarity of the mixed solvent was constructed,which provides a portable,economical in-situ visual inspection strategy that can be practically applied in real life.