气相转移法制备多孔双相沸石复合物

摘要

采用气相转移法制备了同时含有Y和ZSM-5沸石的双相沸石复合物。采用X射线衍射仪(XRD)、扫描电子显微镜(SEM)、N2吸附-脱附和骨架红外(FT-IR)等手段对合成的样品进行了表征。结果表明，合成的样品受Y型沸石的添加量、干胶制备条件和气相转移法转化条件的影响；水热预处理后的ZSM-5沸石前驱体中具有ZSM-5沸石的骨架特征振动峰，归结于 ZSM-5沸石晶核或微晶的形成，这有利于在气相转移法转化过程中引导或促使体系向ZSM-5沸石相的转变，并有利于抑制ZSM-35杂晶的形成； Y型沸石在蒸汽处理过程中的脱铝过程导致合成的沸石复合物具有介孔结构。%A zeolite-zeolite composite composed of Y and ZSM-5 was successfully prepared by a vapor phase transport (VPT) method. The as-synthesized samples were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), N2 adsorption-desorption and FT-IR. The results display that the synthesis is influenced by the Y content, prepar-ing condition of dry gel and transfering condition for VPT method. FT-IR spectra show the characteristic peaks of MFI framework on ZSM-5 precursor after hydrothermal pre-treatment for 16 h. The result can be attributed to the crystal nucleus or microcrystal of ZSM-5 zeolite, either of which may promote growth of ZSM-5 crystals during the VPT proce-dure, and depresse formation of ZSM-35 crystals. The mesopores structure, created in as-synthesized zeolite-zeolite composite, can be ascribed to the extracted aluminum from Y zeolite crystals by VPT procedure.