晶种导向合成不同厚度Zn-ZSM-5用于甲醇制芳烃反应

采用乙二胺与硝酸锌络合物作为Zn物种前驱体，通过加入不同b轴厚度的晶种及尿素水热合成了一系列具有不同b轴厚度的Zn-ZSM-5沸石分子筛。X射线衍射(XRD)、Ar物理吸附和扫描电镜(SEM)的结果显示，Zn物种均匀分布在ZSM-5沸石分子筛中；NH3-TPD和红外光谱结果显示Zn的引入对沸石分子筛的酸性有显著影响；并利用X射线衍射能谱(XPS)探究了Zn物种状态的分布。与传统H-ZSM-5相比，所合成的Zn-ZSM-5催化剂在甲醇制芳烃反应中的选择性和稳定性均显著提高。其中，b轴厚度为100 nm的Zn-ZSM-5-100具有最优异的反应性能，在反应温度为430 ℃、常压且质量空速为3 h-1的条件下，芳烃选择性达到54.4%，催化剂稳定性时间达到156 h。

Synthesis of Zn-ZSM-5 Zeolites of Different Thicknesses by Seed-Oriented Strategy for Methanol to Aromatics

Zn-ZSM-5 zeolites with different b-axis thicknesses were synthesized by using a complex of ethylenediamine and zinc nitrate as Zn precursor,in the presence of seed crystals of different b-axis thicknesses and urea. X-ray diffraction (XRD), Ar physical adsorption and scanning electron microscopy (SEM) show that Zn species are highly distributed in the matrix of zeolite. NH3-TPD and infrared spectra proved that the introduction of Zn has a significant effect on the acidity of zeolites. We also explored the distribution status of Zn species by using X-ray diffraction spectroscopy (XPS). Compared with traditional H-ZSM-5, the selectivity and stability of Zn-ZSM-5 in methanol to aromatics reaction are both significantly improved. The Zn-ZSM-5-100 with b-axis thickness of 100 nm exhibits the highest catalytic performance. Under the conditions of reaction temperature of 430 ℃, atmospheric pressure and mass space velocity of 3 h-1, the selectivity of aromatics is 54.4% and the stability of the catalyst reaches 156 h.