Design,Synthesis And Deviceization Of Functional Covalent Organic Frameworks

Covalent organic frameworks are a new type of crystalline organic porous material that are linked by covalent bonds to form a skeleton structure with specific properties.Its unique advantages are high specific surface area and high thermal stability.,Orderly channel structure and structural function design flexibility.Based on the above characteristics,currently COFs materials have been widely used in storage and separation,catalysis,optics,sensing,biomedicine,etc.,and are a new class of"star"materials.However,COFs are similar to inorganic crystalline materials,and are mostly brittle crystalline powders or particles.Therefore,despite the incomparable advantages of such materials,the materials themselves have the disadvantages of difficult processing and difficult to deviceization.However,the current research focus is still focused on the design and synthesis of new COFs functional materials.COFs deviceization is still limited to the research of COFs film materials,and three-dimensional composites based on COFs materials are still rarely reported.This is a new area that needs to be developed.?.First,four kinds of COFs connected by imine bonds were prepared,namely TpPa-1,TpPa-NO₂,NUS-2 and TpTe-1.Using the ice template method,Pd@TpTe-1 and chitosan are dissolved and dispersed uniformly in a weakly acidic aqueous solution,and 1,4-butanediol diglycidyl ether is used as a crosslinking agent,and the system is strongly stirred to increase the viscosity of the system Into a hydrogel.Then the composite hydrogel is frozen in the refrigerator to a solid in advance,and then transferred to a lyophilizer,and the water vapor is directly sublimated from the solid under ultra-low temperature?-50°C?vacuum conditions,so as to obtain a low density and controllable shape.Composite aerogel material.The generated Pd@TpTe-1@chitosan composite aerogel can be used to construct an efficient continuous flow-through microreactor for dechlorination of CB aqueous solution at room temperature.The freeze-drying method dries the samples under low-temperature vacuum conditions,which effectively avoids the problems of sample oxidation,high-temperature decomposition and deterioration.It is hoped that the method proposed in this work can build more novel and interesting composite materials based on COFs.?.Nano-scale Fe₃O₄@COFs core-shell materials were prepared by growing two-dimensional COFs composed of porphyrin molecules on the surface of Fe₃O₄ nanoparticles,and then used as stabilizers and catalysts of Pickering emulsions for multiphase interface catalysis.It was found that compared with conventional catalytic reactions,the stabilized Pickering emulsion catalytic system of Fe₃O₄@COFs can significantly improve the catalytic efficiency and is stable and reliable.The design of the magnetic core-shell makes the catalyst recovery simple and easy to recycle.?.A two-dimensional COFs material composed of phthalocyanine molecules was prepared,which is expected to be used in photo and electrocatalysis.