多级孔复合沸石的骨架结构与酸性能

Framework and Acidity Properties of Hierarchical Composite Zeolites

多级孔复合沸石是一类具有丰富酸性基的新型催化材料。分别以MOR沸石和ZSM-5型沸石为原料制备了MOR/FAU(记为MFZ)和ZSM-5/FAU(记为MFC)2种复合沸石;采用XRD和FT-IR表征了不同晶化时间合成的MFZ和MFC的结构性能,采用NH3-TPD和Py-IR技术研究了该2种复合沸石催化剂的酸性能,并与单一型沸石催化剂的酸性能进行了对比。结果表明,一种沸石晶体的消失和另一种沸石的生成规律性地体现在复合沸石的形成过程中,揭示了骨架结构性能对复合沸石酸性的影响和调变作用;复合沸石的酸性能明显优于单一型沸石,且可以通过调节复合沸石中某一组分的含量来改变复合沸石的结构,从而达到调节复合沸石的酸量、酸强度和酸性分布的目的。

The Mordenite （MOR） and ZSM-5 zeolites were respectively used as the nutrient of synthesizing composite zeolite, and then the hierarchical composite zeolites of MOR/FAU（MFZ） and ZSM-5/FAU（MFC） with different ratios of two zeolites were prepared. The structural performances of the as-synthesized MFC and MFZ with different crystalline time were characterized by XRD and FT-IR methods. At the same time, their surface acidity were characterized by NH3- TPD and in-situ Py-IR methods, and compared with those of the single type zeolite. The structural effects on the surface acidity in hierarchical composite zeolites were investigated in detail. The results showed that the composite zeolite had obviously more excellent acidity than the single type zeolite. And the acid strength, total acidic amount and acid-typed distribution in the composite could be changed by adjusting the content of two zeolites.