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- Title
A Stable Zinc Zeolite Catalyst for Dehydrogenation of Ethane to Aromatics and Ethylene.
- Authors
Qiu, Baocheng; Zhang, Yakun; Zhang, Yi
- Abstract
The rapid deactivation caused by coke deposits is the major obstacle to the ethane aromatization of Zn-based catalysts. We have successfully synthesized a Zn-embedded inside HZSM-5 crystal catalyst (Zn@HZSM-5) by hydrothermal synthesis using preformed Zn/SiO2 as the only silicone source. Based on various characterization results, including in situ etching XPS, operando DRIFTS, as well as NMR, it is found that Zn(OH)+ and [Zn–O–Zn]2+ species are active sites for ethane aromatization for zinc-based catalysts, and their dynamic transformation significantly changes reaction performance of ethane dehydrogenation. For the Zn/HZSM-5 catalyst, the existence of a large number of [Zn–O–Zn]2+ species causes higher initial ethane conversion and higher selectivity of aromatics, resulting in a large amount of coke deposits. Moreover, [Zn–O–Zn]2+ species on the Zn/HZSM-5 catalyst fast transit to Zn(OH)+ species and subsequently form the sintered ZnO species, leading to rapid deactivation. For the Zn@HZSM-5 catalyst, the embedded structure contributes to forming more Zn(OH)+ species and delays the transformation of the Zn(OH)+ species to [Zn–O–Zn]2+ species, resulting in slowly increased selectivity of aromatics during the reaction. Therefore, the Zn@HZSM-5 catalyst realizes stable ethane conversion with dynamic selectivity.
- Subjects
ZEOLITE catalysts; CATALYSTS; AROMATIZATION catalysts; ETHANES; DEHYDROGENATION; COKE (Coal product); ZINC catalysts
- Publication
Catalysis Letters, 2022, Vol 152, Issue 5, p1372
- ISSN
1011-372X
- Publication type
Article
- DOI
10.1007/s10562-021-03726-1