Degenerating effect of transformation and loss of active sites on NH3-SCR activity during the hydrothermal aging process for Cu-SSZ-13 molecular sieve catalyst. (5th April 2023)

• Record Type: Journal Article
• Authors: Guan, Bin; Zhou, Jiefei; Liu, Ziqian; Wu, Xingze; Wei, Yanfei; Guo, Jiangfeng; Jiang, Han; Lin, He; Huang, Zhen
• Is Part Of: Chemical engineering science. Volume 269(2023)
• Publication Date: 2023-04-05
• Subjects: Active sites -- Copper–aluminum ratio -- Silicon-aluminum ratio -- Hydrothermal aging time and temperature -- Density functional theory; Chemical engineering -- Periodicals; Génie chimique -- Périodiques; Chemical engineering; Periodicals; Electronic journals; 660
• DOI: 10.1016/j.ces.2023.118487
• Languages: English
• ISSNs: 0009-2509

Abstract

Highlights: Exploring the effects of Si/Al ratio and Cu/Al ratio on catalyst activity. Researching the sensitivity of catalyst to aging time and aging temperature. Explaining the reasons for the degradation of catalyst performance caused by hydrothermal aging. Using in-situ DRIFTS experiments and DFT molecular simulation calculations to explore the mechanism. Completing the hydrothermal aging mechanism of Cu-SSZ-13 small pore molecular sieve catalyst. Abstract: A series of Cu-SSZ-13 small-pore molecular sieve catalysts are prepared by the ion-exchange method, analyzed, and tested by changing the synthesis ratio, and performing hydrothermal aging treatment under various aging conditions to explain the degree of influence. The investigations are carried out to reveal that when the Si/Al ratio is 10, the catalyst has the best comprehensive performance and ZCuOH sites are more prone to transformation and loss than Z2 Cu sites during the hydrothermal aging process. In-situ DRIFTS experiments and DFT molecular simulation calculations are used to explain the reasons for the degradation of catalytic performance caused by the hydrothermal aging, which completes the study of the hydrothermal aging mechanism for Cu-SSZ-13 molecular sieve catalysts. The result shows that Z2 Cu active sites exhibit better hydrothermal aging resistance than ZCuOH, the catalyst is more sensitive to aging temperatures than durations, and its limit of the aging temperature is about 850 ℃.