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Research Article | Open Access

“Redox switches” of Fe species on zeolite catalysts: Modulating the acidity and the para-xylene yield from methanol

Qiongfang Hu1,#Hongmei Wang1,#Chaojie Cui1 ( )Weizhong Qian1,2 ( )
Department of Chemical Engineering, Tsinghua University, Beijing 100084, China
Ordos Laboratory, Ordos 017000, China

# Qiongfang Hu and Hongmei Wang contributed equally to this work

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Graphical Abstract

We report a Fe-based redox switch for tuning the acidity of a ZSM-5-based catalyst in themethanol-to-aromatics reaction. The redox switches caused regular fluctuation in the catalyticperformance and remained stable throughout 16 regeneration cycles (up to 80 h).


Molecular switches are widely studied in optical devices, computer science, DNA sensor systems, and chiral synthesis; however, their use in heterogeneous catalytic processes is rarely reported. Herein, we report a Fe-based redox switch for tuning the acidity of a ZSM-5-based catalyst in the methanol-to-aromatics reaction. In this reaction, the yield of the target product, para-xylene (PX), is low because various types of acids on the catalyst activate side reactions. Fe oxides and zeolite generate medium-strength Lewis acids, which activate the aromatization of methanol but suppress the dealkylation of xylene. Gradual reduction of Fe oxides during the reaction simultaneously decreases the conversion of methanol, the yield of aromatics, and the yield of PX. The oxidation state of the Fe species and the associated catalytic performance can be regenerated in the air at 550 °C. The redox switches caused regular fluctuation in the catalytic performance and remained stable throughout 16 regeneration cycles (up to 80 h). The employed strategy enabled a PX yield of up to 60% (carbon base) using a SiO2-coated Zn/P/Fe/ZSM-5 catalyst, which is 3–6 times higher than previously reported values. The result showed a new mode of acidity modulation of the catalyst.

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Carbon Future
Pages 9200001-9200001
Cite this article:
Hu Q, Wang H, Cui C, et al. “Redox switches” of Fe species on zeolite catalysts: Modulating the acidity and the para-xylene yield from methanol. Carbon Future, 2024, 1(1): 9200001.








Received: 11 October 2022
Revised: 03 January 2023
Accepted: 19 January 2023
Published: 19 July 2023
© The Author(s) 2023.

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