Synthesis And Functional Modification Of Metal-Organic Frameworks For Photocatalysis And Proton Conduction

Metal-Organic Frameworks(MOFs),also known as coordination polymers(PCPs),are a group of organic-inorganic hybrid compounds with infinite periodic lattice.Because of their structural diversity and large specific surface area,they show a high potential as functional physical and chemical materials in functional various applications.In the past several decades,MOFs has been intensively studied in gas adsorption and storage,molecular recognition and separation,heterogeneous catalysis and proton conduction applications.In this thesis,the syntheses and functionalized modification of MOFs for the applications in the photo-catalysis and proton conduction are studied.Firstly,two new MOFs with fluorescence response ability were synthesized by hydrothermal method,namely Zr-TCA and Zr12-NBC,and after their basic characterization and photoresponse ability of the two MOFs being tested,the photocatalytic activities of two MOFs for thioether oxidation and trifluoromethylation were tested.Secondly,taking the high stable MOF,UiO-66,as a representative,functionalization by post modification to introduce the sulfonic acid group into its framework was carried out and finally UiO-66-SO3H was obtained via click reaction with UiO-66-NH2 as starting materials,and then after basic characterizations,the proton conduction performance was analyzed.The main research results are shown as below:(1)Taking zirconium metal salt as the inorganic metal ions,triphenylaniline(H3TCA)and triphenylamine(4'-carboxylic acid-1,1'-biphenyl)amine(H3NBC)as organic ligands,two fluorescence MOFs,named as Zr-TCA and Zr12-NBC,were synthesized,respectively,by solvothermal methods,Subsequently,the basic characterizations of two MOFs were carried out by TEM,AFM,PXRD,BET,TGA,UV-Vis and so on.After,the stability and photo-response activities of two MOFs being studied,the photocatalytic thioether oxidation and the photocatalytic trifluoromethylation with the two MOFs as catalysts were studied.The reactions of photocatalytic oxidation of sulfide in the open system at room temperature and atmospheric pressure with light as irradiation source,the results show that both MOFs show high catalytic activities towards a broad of substrates,and the highest catalytic yield of Zr-TCA and Zr12-NBC can reach 98%and 100%,respectively.The reactions of photocatalytic trifluoromethylation were carried out in the atmosphere of nitrogen at room temperature and atmospheric pressure under the irradiation of blue light,the results show that both MOFs have high catalytic activity on various substrates,and the highest catalytic yield can reach more than 99%.The studies show that Zr-TCA and Zr12-NBC are highly promising heterogeneous catalysts for photocatalytic reactions.(2)Taking UiO-66-NH2 as the a staring MOF,after clicked post-modification,the sulfonic acid group was successfully introduced to the skeleton of UiO-66 and UiO-66-SO3H was obtained.The characterization of UiO-66,UiO-66-NH2,UiO-66-N3 and UiO-66-SO3H were analyzed by PXRD,SEM,BET,TGA,FT-IR.Finally,the proton conduction performance of UiO-66,UiO-66-NH2 and UiO-66-SO3H were performed and the results show that the proton conductivity of UiO-66-SO3H is 8.8 × 10-3 S·cm-1 at 98%RH and 80?,while the values of UiO-66 and UiO-66-NH2 are 6.3 × 10-6 and 3.5 × 10-6 S·cm-1,respectively under the same conditions.The observation of the exponential increase revealed that click reaction is a powerful reaction in the functionalization of MOFs towards targeted applications.