Preparation And Catalytic Study Of Metal Nanoparticles/Covalent Organic Frameworks Composites

Covalent organic frameworks(COF),which is a new class of porous crystalline materials constructed by organic molecules through covalent bonds.COF materials have many important applications,such as energy storage,sensing,electron transportation,molecule transportation,separation and catalysis because of their low densities,large surface areas and covalent stabilities.COF materials can be used as functional carriers,which processes the abilities of proton conductivity and catalytic activity when the pore structures adsorbed functional molecule,biological enzyme and nanoparticles.At present,the metal nanoparticles/COF composite materials are mainly prepared through the in-situ preparation of metal nanoparticles inside the pores of synthesized COF material.In this paper,we chose imine COF materials as our research subjects,and then reported a new synthetic method to prepare the composite materials by in-situ encapsulating nanoparticles during the process of synthesizing COF materials.The correlational researches are carried out as the following three aspects:(1)We developed a kind of new strategy to synthesize COF materials based on the solvent thermal synthesis method.TAPB-TP-COF,TAPB-DMTP-COF and COF-300 were chosen as our research objects,and then we successfully synthesized crystal materials with the same structure characteristics as synthesized by traditional synthesis methods by optimizing the concentration of reactants,reaction time,eatalyst dosage and reaction temperature.Afterwards,the growth process of the COF crystals was characterized by different means of characterization methods,and all the possible influencing factors of the growth process were summarized.(2)We prepared metal nanoparticles with different sizes,shapes and species and improved their stabiliy in the reagents to synthesize COF materials by surface modification with PVP.We prepared metal nanoparticles/COF composites by the designed "two-steps" method with the in-situ encapsulation of nanoparticles and studied on their formation process and effect factors.(3)We researched on the catalytic activity of the metal nanoparticles/COF composites in consideration of the catalysis properties of the nanoparticles themselves.After putting the catalytic reaction of 4-nitrophenol as our research model,we studied the catalytic performance of the composites with different nanoparticles.We verified the excellent catalytic activity and structural sta'bility of composites in the cyclic catalytic experiments.