Preparation Of COFs And Their Composite Materials And Applications In Enzyme-like Catalysis And Light Degradation

Covalent organic frameworks?COFs?are one of the most important and active components of porous materials,which are connected by covalent bond.Because of their attractive properties such as lower density,large specific surface area,high crystallinity,high stability,multi-functional structure and easy surface modification,it has attracted the attention of numerous researchers all over the world and has been widely used in the fields of gas and energy storage,detection,adsorption,catalysis,photoelectricity and drug delivery.On the basis of previous work,the following research work has been carried out on the synthesis of reduced COF-300-AR and its composites and their application in catalysis:?1?COF-300-AR was synthesized and characterizated,and was found to have high oxidase-like catalytic activity.TMB-COF-300-AR was used as a new colorimetric method to detect the level of glutathione?GSH?in HL-60 cell lysate.?2?Ultrafine Pt NPs was in-situ prepared based on COF-300-AR as template.The prepared PtNPs@COF-300-AR had good oxadise-like ability,and was used as a new colorimetric system for cellular GSH detection.?3?COF-300-AR as photocatalyst was used to degrade methyl orange,and the corresponding mechanism was studied.This dissertation is divided into five chapters:Chapter 1:Introduction and review of COFs and its classification,synthesis methods and application in catalysis.Chapter 2:For the first time,the reduced COF?COF-300-AR?was used as photosensitive catalyst to catalyze the oxidation reaction of TMB,featured by the oxidase-like ability.On the basis of this,a new method for quantitative determination of GSH in cell extracts was developed using TMB-COF-300-AR as colorimetric platform.Under the optimum conditions,the quantitative detection of GSH in HL60cell extract was successfully realized.The prepared COF-300-AR has good stability and reproducibility even after storage of 15 days and repetive use of 8 cycles.The mechanism study showed that the generation of·OH and O₂^·-free radicals is the main factor to have high catalytic ability.Chapter 3:We designed and synthesized COFs-supported ultrafine platinum nanoparticles?PtNPs@COF-300-AR?by controlling the growth of Pt NPs in virtue of uniformly distributed nitrogen atoms of well-organized framework structures of 3D COFs.Many advantages of PtNPs@COF-300-AR nanohybrids were displayed such as outstanding oxidase-like activity,high stability and easy reusability,which made the TMB-PtNPs@COF-300-AR systema good colorimetric platform for sensitive and selective detection of cellular GSH.Chapter 4:A new method of photocatalytic degradation of methyl orange using the prepared COF-300-AR as photosensitive catalysts was developed.Methyl orange can be degraded almost completely?99%?under the optimal catalytic conditions.The degradation mechanism of methyl orange was studied,and it was proved that the degradation route was mainly quinone degradation.Chapter 5:Conclusions and prospects.