Design,Synthesis And Performance Exploration Of Novel 2D Covalent Organic Frameworks

In recent years,with the continuous development of science and technology,exploration and development of materials are increasingly intense to meet the growing demand.Covalent Organic Frameworks（COFs）,as a new kind of crystalline porous materials,have been gradually drawn into the field of scientists.COF is mainly composed of H,B,C,N,O and other light elements and connected by covalent bonds.It has low density,high specific surface area,high porosity and good stability.Therefore,since the first synthesis of Yaghi in 2005,COF has been developed and widely used in many fields such as catalysis,adsorption,separation,energy storage and bio-medicine.However,the future of COF is far from that.Its long range ordered structure,uniform discrete one-dimensional channels and design modified skeleton give COF unlimited possibilities in application.Therefore,to give full play to the advantages of COF,explore and design new COF is very challenging and meaningful to broaden a broader application field and in-depth performance research.Based on the diversity of COF design and the performance advantage of the material itself,two two-dimensional COF were designed and synthesized in this paper and the corresponding performance was explored.The research content was divided into the following two parts:1、A novel two-dimensional covalent organic framework（JUC-573）with one-dimensional mesoporous channels was prepared by selecting planar two-node and three-node structural elements.The results of PXRD,nitrogen adsorption-desorption and infrared spectroscopy showed that the obtained COF had high crystallinity,high specific surface area and high porosity.Furthermore,in iodine adsorption experiments,JUC-573 showed efficient iodine capture capacity,with the maximum adsorption capacity of 4g·g^-1.This is due to the open channel and high BET and porosity of JUC-573 as a porous material and the accessibility of one-dimensional mesoporous channels in it.Moreover,JUC-573 has excellent recyclable performance,which can be recycled for several times for gaseous iodine adsorption,while maintaining its adsorption capacity almost unchanged2、We synthesized quinone functionalized COF（DAAQ-COF）using 1,6-diaminoanthraquinone as a building block.Through PXRD,nitrogen adsorption-desorption,thermogravimetric analysis and infrared spectroscopy,it was found that DAAQ-COF had high crystallinity,high specific surface area(577 m²·g^-1)and good stability.In addition,metal-free DAAQ-COF exhibited high electrocatalytic oxygen evolution reaction（OER）activity(overpotential:389 m V,Tafel slope:138 m V·dec^-1 at10 m A·cm^-2).This is due to the fact that the introduction of anthraquinone effectively changes the chemical properties and electronic structure of COF skeleton,and the high crystallinity and specific surface area of COF enable the intermediate reactants to more fully contact the active sites of COF and the pores.These results indicate that there is more room for exploration in the field of electrocatalysis by properly designing functional COFs.In summary,we synthesized two kinds of COF,and showed their own unique advantages in gaseous iodine adsorption and electrocatalytic OER applications.This paper shows the potential application prospects of COF,which needs further exploration in the future to give full play to the advantages of COF,so as to shine in more application fields.