【摘要】 多级孔道ZSM-5分子筛因同时具有微孔和介孔结构,在催化领域显示出较好的应用前景。对高硅铝比下以3-氨丙基三乙氧基硅烷作为硅烷化试剂合成具有多级孔道的ZSM-5分子筛进行研究,并采用X射线衍射、N2吸附-脱附和扫描电镜等进行表征。结果表明,合成的多级孔道ZSM-5分子筛是由小晶粒聚集而成的椭球状团簇体,晶粒间会形成介孔;硅烷化试剂的添加量可以在一定程度上调控微介孔比例,介孔孔容随着3-氨丙基三乙氧基硅烷添加量的增加而增大,3-氨丙基三乙氧基硅烷添加量较高时,预晶化与否对多级孔道ZSM-5分子筛的孔结构、形貌和产率产生较大的影响;3-氨丙基三乙氧基硅烷与SiO2物质的量比为0.05∶1时,预晶化条件下合成的样品介孔孔容为0.154 cm3·g-1,明显高于未预晶化条件下合成的样品(0.084 cm3·g-1),产率为91.8%,高于未预晶化条件下合成的样品(65.3%)。更多还原

【Abstract】 Hierarchically porous ZSM-5 molecular sieves combine advantages of micropores and mesopores, exhibiting the promising application in catalytic field. The synthesis of hierarchically porous ZSM-5 molecular sieves with high silica alumina ratio were studied by using 3-aminopropyltriethoxysilane( APTES) as the silanization agent. The as-synthesized samples were characterized by X-ray diffraction,nitrogen adsorptiondesorption isotherms and scanning electron microscopy. The results suggested that ZSM-5 molecular sieve was ellipsoidal aggregates of nanocrystals and mesopores resulted from intercrystalline voids between the primary nanocrystals. Micro-mesoporous volume ratio could be modified to a certain degree by adjusting the amount of APTES,while the mesoporous volume kept positive correlation with the addition amount of APTES. When the addition amount of APTES was comparatively higher,precrystallization had an important impact on pore structure,morphology and the yield of hierarchically porous ZSM-5 molecular sieves. Under the condition of n( APTES) ∶ n( SiO 2) = 0.05∶1 and precrystallization,the mesoporous volume and the yield of as-synthesized sample were 0. 154 cm3·g-1and 91. 8%,respectively,which were higher than those of the sample attained under non-precrystallization( 0. 084 cm3·g-1and 65. 3%).更多还原