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以Beta分子筛为晶核,通过二步水热晶化法成功制备了形态良好的Beta/MCM-22核壳结构复合分子筛。采用X射线衍射(XRD)、扫描电镜(SEM)、透射电镜(TEM)及N2吸附-脱附技术等对分子筛进行了表征。结果表明,复合分子筛形态规整,Beta与MCM-22分别作为核壳而共生;Beta/MCM-22复合分子筛孔结构性质介于MCM-22、Beta分子筛之间。在酸性分布上,复合分子筛的中强酸及B酸所占比例显著增加(CB/CL=13.8)。通过Ar-H2等离子体对Beta分子筛进行处理,使其表面能提高并使表面正电荷富集、硅羟基增加,这是形成良好Beta/MCM-22核壳结构的内在原因。
With Beta zeolite as nucleus, a well-formed Beta / MCM-22 core-shell composite zeolite was successfully prepared by two-step hydrothermal crystallization. The molecular sieves were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and N2 adsorption-desorption techniques. The results showed that the morphology of the composite zeolite was regular and Beta and MCM-22 were coexisted as core and shell respectively. The pore structure of Beta / MCM-22 composite was between MCM-22 and Beta zeolite. In acidic distribution, the proportion of medium-strong acid and B acid in composite zeolite increased significantly (CB / CL = 13.8). The formation of a good Beta / MCM-22 core-shell structure was achieved by treating Beta zeolite with Ar-H2 plasma to increase the surface energy and enrich the surface positive charges.