Synthesis Of Co/Ni-doped Fe-oxygen Cluster-based Metal-organic Frameworks And Their Catalytic Performance For The Selective Oxidation Of Methane

Conversion of methane to liquid fuel as one of the effective strategies for the direct development of naturalgas and biogas,its development and application is extremely urgent.Therefore,the design and synthesis of high quantum efficiency catalyst has became the key to the development of methane conversion technology.In the project,we chose selective methane oxidation as our research object,and try to construct a class of Co/Ni doped Fe-oxo clusters based Metal-organic framework catalysts through modularization.On one hand,with doped Co/Ni ions in Fe-oxo clusters,we can conveniently and controllably synthesize and stabilize the Fe-oxo clusters based Metal-organic frameworks.On the other hand,the structure of the iron oxide clusters fitted into the catalysts is similar to the active sites of methane monooxygenase（MMO）in nature,which makes the catalysts have the ability to solve selective oxidation of methane.Two series of Co/Ni doped Fe-oxo clusters based MOFs were synthesized by solvothermal method using[Fe₂M（μ₃-O）（CH₃COO）₆]clusters as starting materials,and their catalytic performance for methane selective oxidation in liquid phase was studied.This paper mainly includes the following two parts:1.A series of Co,Ni doped metal organic frameworks ETTC（Fe）were designed and synthesized by solvothermal method using tetrastyryl carboxylic acid ligand.These MOFs have three-dimensional interpenetrating structures.Through the study of the liquid phase catalytic selective oxidation of methane on this series of MOFs materials,it is found that at 50°C,3 Mpa CH₄,0.5 M H₂O₂ for 1 hour,the liquid phase catalytic productivity of ETTC（Fe Ni）for the oxidation of methane to methanol is 180.2μmolg^-1_catalysth^-1 with good selectivity and cycle stability.2.[Fe₂M（μ₃-O）（CH₃COO）₆]clusters were used as starting materials to synthesize a series of CO and Ni doped metal organic frameworks PCN-250（Fe）by solvothermal method.These MOFs have a three-dimensional structure.Through the study of the liquid phase catalytic selective oxidation of methane on this series of MOFs materials,it was found that the PCN-250（Fe₂Ni）liquid phase catalyzed the oxidation of methane to acetic acid after reacting for1 hour under the conditions of 50°C,3 Mpa CH₄-Ar syngas,and 0.05 M H₂O₂.The productivity is 107.31μmolg^-1_catalysth^-1 with good cycle stability.