Preparation Of Zirconium-based Metal Organic Framework Material UiO-66 And Study Of Its Adsorption And Catalytic Performance

Metal-organic frameworks material（MOFs）is a new kind of porous nanomaterials that constructed by coordination self-assembly of metal nodes and organic linkers.MOFs possess high specific surface,diverse and adjustable structure,high porosity and flexible tailorability,which has significant advantages in performance compared with other porous materials.Therefore,they have broad potential in a wide of fields such as gas storage and separation,catalysis,sensing,adsorption and biomedicine,etc.UiO-66 is a typical zirconium metal-organic framework with good thermal and chemical stability and has obtained outstanding achievements in adsorption and catalysis.Herein,based on UiO-66 that was prepared by a mild and rapid synthesis method,the effect of water on structure and the adsorption property on methylene blue dye were studied.On the other hand,UiO-66 was used as carrier of alloy nanoparticles,then supported nanocatalysts were synthesized and the catalytic hydrolysis performance of hydrazine hydrate over them was studied.The main research work is as follows:（1）UiO-66 with typical structure was successfully synthesized by two-step synthesis method at room temperature.The effects of ethanol and water on the structure of the product UiO-66were studied.The results show that the addition of ethanol and water could reduce the specific surface area and crystallinity of UiO-66,while the addition of water had little effect on the structure and morphology,but led to the agglomeration of grains.UiO-66 and UiO-66（x）were used as adsorbents for the adsorption of methylene blue solution.As a result,it was found that UiO-66 showed better adsorption capacity with a maximum adsorption capacity of 543mg g^-1 and good stability.The effect of other factors such as the solution pH,initial concentration,adsorption time and the amount of adsorbent on the perfirmance of adsorption were also been studied.It is found that 10 mg UiO-66 has higher adsorption capacity on methylene blue in alkaline environment when the solution pH is 10,which could achieve adsorption equilibrium in 90 min and its capacity gradually increase along with the increase of concentration and then reach balance.（2）The metal particles were successfully fixed on UiO-66 by simple chemical reduction method and catalysts with different proportions were prepared by adjusting the ratio of metal ions in the precursor.The catalyst was characterized by ICP,SEM,TEM,XRD,BET,XPS and other characterization methods.The results show that the ratio of NiFePd in the catalyst could be regulated with change of precursor metal ions.Ni and Fe mainly exist in oxidation state while Pd is zero-valent metal,forming a nanosheet structure covered on UiO-66.The catalytic hydrolysis of hydrazine hydrate by the catalyst was investigated.The result show that the carrier UiO-66 has no catalytic activity,and tri-metal supported catalyst Ni_0.25Fe_0.25Pd_0.5/UiO-66 shows the best catalytic performance with a TOF value of 662 h^-1.Moreover,the catalyst with good stability could be reused to the catalytic reaction in practice.