Synthesis Of Ordered Macro-microporous Covalent Organic Frameworks Single Crystals And Their Application In Iodine Adsorption

Colvalent Organic Frameworks(COFs)is a kind of porous crystal materials constructed by small organic molecules through covalent bonds.Due to their low density,stable chemical properties,large specific surface area and adjustable pore,they have important application potential in energy storage,catalysis,sensing,adsorption and other fields.In recent years,although the synthesis methods of COF materials have been developed rapidly,the products obtained by traditional methods are mainly in the form of polycrystal.Relatively speaking,the synthesis of COF single crystals is still in the development stage,but large size single crystals will be more conducive to our systematic exploration of the relationship between the structure and properties of covalent organic frameworks,so as to further optimize their performance in various applications.However,with the increase of single crystal size,the effective diffusion of guest molecules in COF micropores has become one of the problems to be solved in many applications.This paper mainly studies the synthesis of covalent organic skeleton large single crystal,the introduction of ordered macropore structure in COFs single crystal and the relationship between the structure and performance of covalent organic skeleton through the application of ordered macropore covalent organic skeleton single crystal of iodine adsorption,which can be divided into the following three aspects:(1)Based on the synthesis of ordered macroporous COF-300 single crystal by hard template method,the preliminary experimental results were optimized,and the effects of various variables on the results were deeply studied.The morphology and yield of ordered macroporous COF-300 single crystal were optimized,and the ordered macroporous COF300 single crystal with high quality,high yield and high crystallizability were obtained.(2)The universal validity of the hard template method for the synthesis of ordered macro-microporous COFs single crystals was verified.COF-303 single crystal and DHPTAPM-COF single crystal were respectively tried,and the hard template method was successfully applied in the two kinds of COFs single crystals to synthesize the COF-303 single crystal and the ordered macro-microporous DHP-TAPM-COF single crystal.The structure of the product is complete and the morphology is clear.(3)In order to study the diffusion problem in covalent organic skeleton materials and better understand the relationship between its structure and properties,we conducted a study on the iodine adsorption of COF-300 with the introduction of ordered macroporous structure.By comparing the iodine adsorption efficiency and maximum adsorption capacity of COF-300 before and after the introduction of macroporous structure,It was found that the iodine adsorption efficiency and capacity of COF-300 single crystal were greatly improved by the introduction of macroporous structure.