Study On The Synthesis And Properties Of Framework Material UIO-66?H₂ADC? With Zr⁴⁺ As The Central Ion And 9,10-dicarboxylic Acid Anthracene As The Ligand

Metal organic frameworks?MOFs?are a novel type of crystal structuredfunctional materials,which are formed by metal ions or metal clusters and organic ligands.With high specific surface area and pore structural diversity,MOFs show important applications in catalysis,gas storage and separation,however,for most of these are relatively low physicochemical stabilities,such as water,acid-base,and thermal stability,meanwhile it is slow for the research progress of functional MOFs On the hydrogen adsorption.Therefore,it is the common goal for researchers to synthesis functional MOFs with high stability and high hydrogen storage properties.Inthis article,a new nano dimethyl-functionalized UIO-66 type frameworks,UIO-66?H₂ADC?,was synthesized by two different methods?solvent thermal and simple solution method?,with 9,10-dicarboxylic acid anthracene as ligand and Zr⁴⁺ as the central ion.The synthesized products were characterized by PXRD,FT-IR,TG-DTG,and thehydrogen adsorption properties and stability test?acid,water and alkali?are studied.The results showed that the structures maintain their stabilityin environments of nitric acid,triethylamine,and boiling water,moreover,high hydrogen storage performance.The followings are the main research work.1.9,10-dicarboxylicacid anthracene was synthesized according to the process listed in the references.Specific synthetic process: the 9,10-brominated anthracene was obtained by the bromide of the anthracene,then,the yellow powder,9,10-anthracene dicarboxylic acid,was prepared by the reaction of 9,10-brominated anthraceneand CO2,finally,the structure of 9,10-dicarboxylic acid anthracenewas characterized by FTIR andH1 NMR.2.A new nano yellow powder material of zirconium metal organic framework material,denoted as UIO-66?H₂DCA?,with 9,10-dicarboxylic acid anthraceneas ligand and Zr⁴⁺ as the central ion,was synthesized by two different methods?solvent thermal and simple solution method?and the effect of the reaction temperature,reaction time and the mole ratio synthesis of UIO-66?H₂DCA?was studied,at the same time,the UIO-66 were synthesized by solvent thermal and their structurewas characterized and analyzed by PXRD,the characterization results of PXRDshows that UIO-66?H₂ADC?has the same topological structure as UIO-66.3 The BET area and Langmuir surface areas for UIO-66?H₂ADC?-1 tested by N₂ ad sorption at 77 K are 432m2/g and487 m2/g,respectively,and the BET area and Langmuir surface areas for UIO-66?H₂ADC?-2 tested by N₂ ad sorption at 77 K are 715m2/g and1028m2/g,respectively.TheTG-DTG of UIO-66?H₂ADC?-1 analysis shows weight loss at 583 K-773 K is in virtue of the furtherdecomposition of UIO-66?H₂DCA?-1 to form carbonaceous material and ZrO2.The structural stabilityof UIO-66?H₂DCA?-1was testedin water,different types of acid and alkali compounds.Importantly,we found that the structures maintain their stability in environments of nitric acid,triethylamine,and boiling water.4.The high-pressure isotherms of hydrogen adsoption for UIO-66?H₂ADC?-1?UIO-66?H₂ADC?-2?UIO-66 exhibits the hydrogen adsoption of UIO-66?H₂ADC?-2 is the higher than the others.Their hydrogen adsoption were: 2.19wt%,2.38wt%,1.28wt%at 298 K.5MPa.The hydrogen adsorption capacity of UIO-66?H₂ADC?is about 1.8 times than the hydrogen adsorption capacity of UIO-66.The result shows compared with terephthalic acid,the ligand of 9,10-dicarboxylic acid anthracene?H₂DCA?,which involves two more molecules benzene,was added by forming a larger conjugated ? bond to enhance the new type of hydrogen storage properties of MOFs.