Structural effects of hierarchical pores in zeolite composite
Structural effects of hierarchical pores in zeolite composite
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DOI：
10.1016/j.micromeso.2009.03.009
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发表时间：
2009-06
影响因子：
5.2
通讯作者：
Jiajun Zheng;Xiwen Zhang;Yan Zhang;Jinghong Ma;Ruifeng Li
中科院分区：
文献类型：
--
作者：
Jiajun Zheng;Xiwen Zhang;Yan Zhang;Jinghong Ma;Ruifeng Li
采用两步水热结晶法制备了具有MFI和MOR沸石结构的沸石复合材料（记为MMZ），并通过X射线粉末衍射、氮气吸附-脱附、扫描电子显微镜和原位红外光谱对吡啶和2,6-二甲基吡啶进行了表征。研究了复合MMZ在正辛烷和异丙苯催化裂化过程中的酸催化作用。结果表明，在沸石复合材料中创建了分级孔系统，提高了复合材料中酸性位点的可达性和扩散性。当使用2,6-二甲基吡啶作为探针分子时，复合材料中的扩散率比相应的物理混合物高约7倍，并且复合材料中的酸可及性是物理混合物中的3.4倍。在 423K 下，H-MMZ 上枯烯的转化率是物理混合物上的转化率的三倍。
A zeolite composite with MFI and MOR zeolite structures (denoted as MMZ) was prepared by a two-step hydrothermal crystallization, and characterized by X-ray powder diffraction, nitrogen adsorption–desorption, scanning electron microscopy and in situ IR spectrometry of pyridine and 2,6-dimethyl pyridine. The acid catalysis of the composite MMZ was investigated during the catalytic cracking of n-octane and cumene. The results showed that a hierarchical pore system was created in the zeolite composite improving the accessibility of acid sites and diffusivity in the composite material. The diffusivity in the composite was about seven times higher than in the corresponding physical mixture, and the acid accessibility in the composite was 3.4 times as much as in the physical mixture when 2,6-dimethyl pyridine was used as the probe molecule. The conversion of cumene on H-MMZ was three times larger than that on the physical mixture at 423K.