高硅ZSM-5沸石孔道和酸性的协同调控及其催化甲醇制丙烯反应性能

通过碱处理结合铬改性策略实现了对高硅 ZSM-5沸石孔道和酸性的协同调控, 制备出了一种具有适宜酸性的高硅多级孔沸石催化剂。在碱处理的过程中, 通过精细调节合成凝胶组成, 在沸石晶体中引入的丰富共生界面, 诱导了介孔的形成, 从而打破了沸石硅铝比对常规碱处理法的限制。在铬改性的过程中, 独特的多级孔结构促进了铬在催化剂中的分散, 从而实现了对酸性的深度改性。在甲醇制丙烯催化反应中, 制备的催化剂表现出了极佳的催化稳定性以及很高的丙烯和总低碳烯烃选择性。

High-silica ZSM-5 zeolite: Synergistic regulation of pore structure and acidic property and catalytic performance in methanol to propylene reaction

Combined strategy of alkali treatment and chromium modification was used to synergistically regulate the pore structure and acidic property of the high-silica ZSM-5 zeolite. During the alkaline treatment, the abundant intergrowth boundaries constructed by adjusting the composition of the synthesis gel induced the formation of meso-pores. Thereby, the limitation of the conventional alkali treatment method coming from the framework Si/Al ratio of parent zeolite was circumvented. In the process of chromium modification, the unique hierarchical pore structure promoted the dispersion of chromium species in the catalyst. Thus, a deep modification of the acidic property was realized. As a result, a high-silica hierarchical zeolite catalyst with suitable acidities was obtained. During the cata-lytic conversion of methanol to propylene, the variation of the pore structure and acidic property caused obvious changes in the coke deposition behavior of the catalyst and the mass transfer of products. Consequently, the pre-pared catalyst exhibited excellent catalytic stability and a high selectivity towards propylene and total light olefins.