文献类型：期刊文献

英文题名：Simultaneously enhanced aromatics selectivity and catalyst lifetime in methanol aromatization over [Zn, Al]-ZSM-5 via isomorphous substitution with optimized acidic properties and pore structure

作者：Liu, Xinhui[1];Yan, Chen[1];Wang, Yilin[1];Zhang, Peng[1];Yan, Siyan[1];Zhuang, Jianguo[1];Zhu, Xuedong[1];Yang, Fan[1]

机构：[1]East China Univ Sci & Technol, Engn Res Ctr Large Scale Reactor Engn & Technol, Minist Educ, Shanghai 200237, Peoples R China

年份：2023

卷号：349

外文期刊名：FUEL

收录：;EI(收录号：20232214169669);WOS:【SCI-EXPANDED(收录号:WOS:001009706800001)】；

基金：The authors are grateful for the financial support from the National Natural Science Foundation of China (21776076) and the Fundamental Research Funds for the Central Universities (JKA01211710) . The au- thors also thank the Research Center of Analysis and Test of East China University of Science and Technology for the help with the characterizations.

语种：英文

外文关键词：Isomorphous substitution; Acidic properties; Pore structure; Methanol aromatization

摘要：Zinc-modified HZSM-5 zeolites as efficient catalysts have been widely applied in methanol to aromatics (MTA) reactions, however, the relationship between aromatics selectivity and catalytic stability in traditionally loaded catalysts seems to be a stubborn trade-off. To improve both catalytic indicators simultaneously and reveal the relation of the states of introduced Zn species to the consequential influence in physiochemical properties, a series of [Zn, Al]-Z5 zeolites with different Zn contents were prepared via isomorphous substitution under a fixed Si/Me (Me = Al or Al and Zn) ratio. Results revealed that there were three possible states of the introduced Zn species, namely the highly-dispersed ZnO phase, the Zn(OH)+ occupying the ion-exchange sites, and the tetracoordinated ZnO4 2- integrated into the zeolite framework. A portion of Zn was successfully integrated into the five-membered rings of zeolite in the form of Si-O(H)-Zn, which played the role of strong Bro center dot nsted acid sites and led to the formation of hierarchical structures aside from the intrinsic micropores. Besides, extra-framework Zn (OH)+ was formed by the interaction between dissociate Zn species and the Si-O(H)-Al structure, giving rise to larger proportions of Lewis acid sites. Benefitting from the optimized acidic properties and pore structure, 0.5 [Zn, Al]-Z5 exhibited higher aromatics selectivity and longer catalyst lifetime (26.0% and 132 h) than [Al]-Z5 without Zn addition (19.6% and 52 h) in methanol aromatization. Overall, our findings opened a new way to improve the efficiency of MTA reaction and broadened the method to obtain metal-modified zeolite catalysts.