The Preparation And Modification Of Metal Organic Frameworks And Research Hydrogen Storage Properties

As more and more attention is paid to the utilization of hydrogen energy,researchers are working to develop better hydrogen storage technology.The use of porous materials for hydrogen storage can effectively overcome the disadvantages of high cost and difficulty of operation when campare to the hydrogen storage technologies such as high-pressure gas tank,liquefying.As a new type of porous materials,metal organic frameworks have the characteristics of high specific surface,high pore volume and pore structure,therefore,metal organic framework materials have broad application prospects in hydrogen storage.In this paper,MOF-5 was chosen as the research object to study the effect of synthesis conditions on the adsorption properties of MOF-5.At the same time,modification were studied by dope the copper and nickle in the structure of MOF-5,and investigate the hydrogen storage properties of the modified materials.The hydrogen adsorption properties of MOF-5 crystal prepared in different temperature（100℃,120℃,150℃）and different reaction time（12h,16 h,24h）were tested,it was found that when the reaction temperature is 120℃ and the reaction time is 16 h,the MOF-5 has good crystal structure and the adsorption property of the crystal material is the best.It was found that the doping of nickel can effectively improve the stability of the structure of the material.When Zn/Ni is 9:1,8:2,7:3 in the synthetic solution,the hydrogen storage performance of the prepared crystal material Ni-MOF-5 increased.However,when the Zn/Ni ratio increases,the hydrogen storage performance of the material decreased.When the Zn/Ni is 9:1 in the synthetic solution,the addition of ethanol in the solvent will lead to the adsorption performance of the material increases with the increase of ethanol content in the solvent,with the increase of ethanol content in the solvent,the adsorption properties of the material will decrease gradually.When the Zn/Ni is 9:1 in the synthetic solution,the hydrogen adsorption performance of Ni-MOF-5,which was prepared by adding ethanol solution in the solvent,showed a decreasing trend.The Ni-MOF-5 material was purified by two ways: "DMF+CH₃OH" and "DMF+CH₃COCH₃",the experimental results show that the sample treated with "DMF+CH₃COCH₃" method has better adsorption hydrogen storage performance.The addition of copper in the MOF-5 framework can also improve the stability of crystal materials.When Zn/Cu is 9:1,8:2,7:3 in the synthetic solution,the hydrogen storage properties of the prepared crystal material Cu-MOF-5 have been improved to some extent.When the Zn/Cu was 7:3,the hydrogen storage properties of the material can reach 1.67wt%.By comparing the difference of adsorption properties of Cu and Ni doped MOF-5,it can be found that the loading of copper and nickel in the MOF-5 framework can improve the hydrogen storage properties of the materials.However,the adsorption performance is related to the amount of metal doping.