The Synthesis And Characterization Of Transition Metal Substituted MMS

Mesoporous molecular sieves(MMS)have uniform and tunable pore size,ordered pore arrays,large ratio surface areas and large pore volumes and have their advantage:functionality and structure,thereby offering considerable potential for wide use in catalysis,separation,nano-optical apparatus and chromatogram carrier.With catalyzing,MMS can be used as catalyst carrier in order to enhance efficiency of catalyst.In addition,polyoxometalates have their unique advantages:multi functionality and structure mobility.Among numerous applications of polyoxometalates, catalysis has been widely recognized as one of the most important.POM can be used as Bronsted acidic catalysts,oxidation catalysts,or bifunctional catalysts.If POM be carried on MMS,the efficiency of catalyst also can be enhanced.According this,in the experimentâ… synthesize M-MMS by Sol-Gel method,where I add metal source into the incipient solution directly.The samples were characterized by various physicochemical methods,including XRD,N₂ adsorption-desorption isothermal,XPS,XDE.The experiment include two sections: First:Zinc incorporated MCM-48 molecular sieves have been synthesized from the incipient gel by direct mixed-gel,where metal source is[Zn(OH)₂].The samples were characterized by XRD,N₂ adsorption-desorption isothermal,XPS.The effects of Si/Zn ratio on the structure of synthesized composite molecular sieves are investigated.Second:polyoxometalates are sources.When polyoxometalates in the form of tetrabutylammonium salts or tetraethylammonium salts, which are not soluble in water,but have great solubility in polar organic solvents such as acetonitrile and DMSO.In the incipient cosolvent,â… synthesize various M-MMS including Mo-MCM-41,Mo-MCM-50,W-MCM-50,V-MCM-50,[Pd,V]-MCM-50,[Cu,V]-MCM-5,Mo-HMS,W-HMS,V-HMS and TBA₄H[PW₁₁Mn(H₂O)O₃₉]containing-MCM-50 from the incipient gel by direct mixed-gel.The samples were characterized by various physicochemical methods,including XRD,N₂ adsorption-desorption isothermal,XPS,XDE.The results reveal that the sieves containing various metal or POM have nannow pore size distribution,regular pore structure and high surface areas and metal or POM are incorporated in pore wall of MMS with well-dispersed state.