Inorganic Chemicals Industry ›› 2025, Vol. 57 ›› Issue (12): 123-130.doi: 10.19964/j.issn.1006-4990.2024-0642

• Catalytic Materials • Previous Articles    

Study on effect of potassium on deNO x performance and hydrothermal stability of Cu-SSZ-13 catalysts

FENG Xi1,2(), LÜ Liang1(), SUN Rui1, LAI Yineng1, YANG Lan1, WANG Ruifang1,2()   

  1. 1. SINOTECH Company Limited,Chengdu 611731,China
    2. State Key Laboratory of Polymer Materials Engineering of China(Sichuan University),Polymer Research Institute of Sichuan University,Chengdu 610065,China
  • Received:2024-11-28 Online:2025-12-10 Published:2025-12-29
  • Contact: Lü Liang, WANG Ruifang E-mail:fengx@sinocat.com.cn;lvl@sinocat.com.cn;wangrf@sinocat.com.cn

Abstract:

To explore the mechanism of the synergistic effect of chemical poisoning and high-temperature hydrothermal aging on the NH3-SCR performance of Cu-SSZ-13 catalysts,various samples were generated by subjecting the catalysts to poisoning and high-temperature treatment on an engine test bench.The physicochemical properties of catalyst coatings at different locations within the monolithic catalyst were investigated by using BET,SEM,NH3-TPD,and H2-TPR.The results revealed that K deposition on the fresh catalyst displaced isolated Cu2+ and protons on framework Brønsted acid sites,leading to a reduction in the number of active Cu2+ ions in the catalyst framework,a decrease in acidity without crystal structure damage,and partial pore blockage.During the high-temperature hydrothermal aging process,the presence of K exacerbated the collapse of the zeolite framework and accelerated the transformation of Cu2+ into Cu x O y species,which in turn inhibited the recombination of Al(OH)3,leading to a significant decrease in specific surface area and redox properties.The deNO x activity of the catalyst was examined by means of a fixed-bed reactor,and it was found that K weakened the activity and undermined the hydrothermal stability of the catalyst.After poisoning,the deNO x efficiency of CZ at 200 ℃ and 500 ℃ was decreased from 92.84% and 89.38% to 85.64% and 83.22%(KCZ-1),respectively.After aging,the deNO x efficiency of KCZ-HT1 at 200 ℃ and 500 ℃ was further deteriorated to 74.24% and 76.02%,a decrease of 15.7% and 10.8% compared to the unpolluted aged sample(CZ-HT).In addition,the deposition of K in the catalyst was decreased along the gas flow direction,and the higher deposition at the front end resulted in poorer stability of the catalyst than at the back end.These findings provided an important basis for optimizing the design of anti-poisoning catalysts.This study clarified the mechanism by which K synergistically deteriorated catalyst activity and high-temperature hydrothermal stability through proton displacement and active site competition,etc,highlighting the sensitivity of D6R site Cu2+ to K poisoning and the significant impact on the stability of 8MRs site Cu2+ during aging,providing a theoretical basis for the targeted design of anti-poisoning catalysts.

Key words: Cu-SSZ-13, K poisoning, high-temperature hydrothermal stability, NH3-SCR, deNO x performance

CLC Number: