Unraveling alkali-tolerance role of zeolite coupling CeWOx catalyst for NOx reduction

• Published in: Applied catalysis. B, Environmental Environmental, 2023-10, Vol.334, Article 122872
• Main Authors: Li, Gang, Li, Yonglong, Han, Dong, Liu, Wenming, Liao, Meiyuan, Chen, Lei, Wu, Daishe, Li, Zhenguo, Wei, Linsheng, Lu, Shengyong, Peng, Honggen
• Format: Article
• Language: English
• Subjects: Ammonia selective catalytic reduction; CeWOx; K-poisoning resistance; Nitrogen oxides; Zeolite
• ISSN: 0926-3373; 1873-3883
• DOI: 10.1016/j.apcatb.2023.122872

The deactivation of the selective catalytic reduction (SCR) catalysts in the presence of alkali metal is still unsolved to date, there is no fully effective strategy to remedy it. Herein, a series of novel zeolite coupling CeWOx catalysts (CeWOx@ZSM-5) with core-shell structures was synthesized by a simple method. The proposed CeWOx@ZSM-5 catalyst exhibited superior deNOx performance and K-poisoning resistance, which are attributed to the synergy between the shell and active components. The zeolite shell with abundant acid sites can act as a sacrificial agent to preferentially bind to K, thereby decelerating/inhibiting the alkali metal poisoning process of the catalyst. Even after loading 1 wt% K, the NOx conversion remained as high as > 80% at 300–500 °C over the CeWOx@ZSM-5 catalyst under humid conditions. The novel zeolite coupling CeWOx catalyst may serve as a workable reference for new, efficient, and highly poisoning-resistant SCR catalysts for practical application. [Display omitted] •CeWOx@ZSM-5 catalyst with excellent deNOx performance was prepared.•CeWOx@ZSM-5 was designed through a coupling zeolite and metal oxide strategy.•The abundance of acid sites on ZSM-5 is the main reason for improving the catalyst resistance to K-poisoning.•The acid site on the ZSM-5 molecular sieve is the preferred sacrificial site for K-poisoning.•The shielding effect of the ZSM-5 shell layer effectively avoids direct contact of K with the active site (CeWOx).