Inhibition of Cu-SSZ-13 for NH3 Selective Catalytic Reduction by K/Na Poisoning.

Autor: Zhou, Jiefei, Guan, Bin, Guo, Jiangfeng, Chen, Junyan, Liu, Ziqian, Zheng, Chunzheng, Su, Tianxu, Zhang, Yaoyao, Yuan, Yuheng, Dang, Hongtao, Xu, Bingyu, Xu, Chengze, Zeng, Wenbo, Huang, Zhen
Předmět:
Zdroj: Catalysis Letters; Jun2024, Vol. 154 Issue 6, p2761-2776, 16p
Abstrakt: Cu/SSZ-13 is considered to be a promising material for NH3-SCR catalysts. However, in practical applications, Cu/SSZ-13 is inevitably exposed to alkali metal deposition. In this paper, Cu/SSZ-13 molecular sieve catalysts were prepared by the ion exchange method, catalysts with different degrees of alkali metal K/Na poisoning were prepared by the wet-impregnation method, and the SCR activity and N2 selectivity of fresh and poisoned catalysts were compared. The effects of alkali ion (Na+ and K+) poisoning on the comprehensive properties of Cu/SSZ-13 were studied. The distribution and quantity of Cu2+ active components in the catalyst before and after poisoning and the change of acidic sites were explored using NH3-TPO, NH3-TPD, H2-TPR, BET, and XRD. The characteristics of crystal structure, specific surface area, and pore structure revealed the influence of the loading of alkali metal K/Na on the adsorption performance, weakened redox characteristics, and a certain degree of structural damage of Cu/SSZ-13 molecular sieve catalyst. It explains that the reason for the decline in catalyst performance after poisoning is due to the decrease in the number of active sites caused by the ion-exchange between alkali metal ions and Cu2+ and H+, the increase of CuxOy species, the decrease of acidic sites, and pore blockage. This provides data support and theoretical basis for the design of highly resistant Cu/SSZ-13 catalysts. [ABSTRACT FROM AUTHOR]
Databáze: Complementary Index