Abstract
Cu-SSZ-13 small-pore zeolites have been commercialized for NOx abatement in diesel engines, while they still suffer from hydrothermal deactivation. To identify the changes occurring in catalysts during the whole hydrothermal aging (HTA) process, the selective catalytic reduction by ammonia (NH3-SCR) performance of hydrothermally aged catalysts was investigated until total deactivation occurred. Through precisely identifying the alterations in the zeolite framework and active Cu sites during HTA, three stages were distinguished under progressively more severe HTA conditions, which were dealumination/transformation of active Cu species, CuOx accumulation, and structural collapse. These three stages were found to cause a slight decrease, serious attenuation, and total deactivation of the deNOx efficiency, which stemmed from the loss of Bronsted acid sites, reduction in the number of active Cu ion sites and structural collapse, respectively. This work also depicted simulated deactivation curves of Cu-SSZ-13 with various compositions during the HTA process, which helps in understanding the hydrothermal aging limits of catalysts with various Si/Al ratios and Cu loadings.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
