One-pot green synthesis of Fe-ZSM-5 zeolite containing framework heteroatoms via dry gel conversion for enhanced propylene selectivity of catalytic cracking catalyst
One-pot green synthesis of Fe-ZSM-5 zeolite containing framework heteroatoms via dry gel conversion for enhanced propylene selectivity of catalytic cracking catalyst
复制标题
干凝胶转化一锅法绿色合成含骨架杂原子Fe-ZSM-5沸石提高催化裂化催化剂丙烯选择性
DOI：
10.1007/s10853-021-06472-2
复制
发表时间：
2021
影响因子：
4.5
通讯作者：
Yan Zifeng
中科院分区：
文献类型：
--
作者：
Wang Youhe;Li Tingting;Li Chencan;Lu Jinzhi;Dai Chang;Subhan Fazle;Bai Peng;Sun Hongman;Feng Rui;Yan Zifeng
由于Fe-ZSM-5分子筛在不同领域的广泛应用，开发一种可持续的合成途径具有重要意义。本文报道了一种新颖、高效、环保的干凝胶转化方法，在不添加模板和种子晶体的情况下，一锅合成了含框架杂原子的Fe-ZSM-5分子筛。该方法不仅提高了沸石的合成效率，而且避免了使用普通模板，降低了成本和环境污染。采用XRD、n2吸附-脱附、SEM、uv -可见漫反射、XPS、FT-IR和NH3-TPD等技术对合成样品的理化性质进行了分析。表征结果表明，一锅法合成的Fe-ZSM-5沸石（Fe-ZSM-5- in）中的Fe主要以Fe3+的形式存在于沸石骨架中，而浸渍法制备的Fe/ZSM-5沸石（Fe/ZSM-5- im）中的Fe主要以Fe3+的低聚簇和fe2o3颗粒等非骨架形式存在于沸石表面。与Fe/ZSM-5-Im相比，Fe- zsm -5- in具有更高的酸量和更好的框架Fe3+分布。催化性能评价结果表明，Fe改性ZSM-5添加剂由于酸含量和酸强度的提高而提高了丙烯收率。与Fe/ZSM-5-Im添加剂相比，Fe- zsm -5- in添加剂由于酸含量较高，脱氢活性较低，丙烯收率较高，焦炭收率较低。摘要在不添加模板和种子晶的情况下，采用干凝胶转化法（DGC）一锅法合成了含框架杂原子的Fe-ZSM-5分子筛，该分子筛在催化裂化过程中表现出比Fe/ZSM-5添加剂更高的催化活性和丙烯收率。
Development of a sustainable route for the synthesis of Fe-ZSM-5 zeolites is important due to their diverse applications in different fields. Herein, we report a novel, efficient and an eco-friendly dry gel conversion method to one-pot synthesize Fe-ZSM-5 zeolite containing framework heteroatoms under the conditions that neither the template nor the seed crystal was added. The present strategy not only improves the synthesis efficiency of zeolites, but also reduces the cost and environmental pollution by avoiding using ordinary template. The physicochemical properties of the synthesized samples were analyzed by XRD, N2adsorption–desorption, SEM, UV–visible diffuse reflectance, XPS, FT-IR and NH3-TPD techniques. The characterization results revealed that the Fe species in the one-pot synthesized Fe-ZSM-5 zeolite (Fe-ZSM-5-In) mainly exist in the zeolite framework in the form of Fe3+, while those in the Fe/ZSM-5 zeolite prepared by impregnation (Fe/ZSM-5-Im) mostly exist on the surface of the zeolite in the form of non-framework Fe such as oligomeric Fex3+Oyclusters and Fe2O3particles. Fe-ZSM-5-In possessed enhanced acid amount and better distribution of framework Fe3+species than Fe/ZSM-5-Im. The results of catalytic performance evaluation show that the propylene yield is improved by the Fe modified ZSM-5 additives due to enhanced acid content and acid strength. Compared with the Fe/ZSM-5-Im additive, the Fe-ZSM-5-In additive has higher propylene yield and lower coke yield owing to its more acid content and lower dehydrogenation activity.Graphical AbstractThe Fe-ZSM-5 zeolite containing the framework heteroatoms was one-pot synthesized by the dry gel conversion (DGC) method under the conditions that neither the template nor the seed crystal is added, which exhibits improv ed catalytic activity and has higher propylene yield than the Fe/ZSM-5 additive in the catalytic cracking process.