Deactivation of Cu/Zeolite SCR Catalyst Due To Reductive Hydrothermal Aging

Temperature programmed reduction by CO, H₂, and propylene (C₃H₆), as well as hydrothermal aging in the presence of mixture of NO, HC, CO, H₂ and O₂ were used to study the deactivation of Cu/zeolite SCR catalysts. The presence of CO had no detrimental effect on catalyst activity. Carbonaceous deposit on the catalyst surface from propylene (C₃H₆) reduction suppressed the catalyst activity and burn off of carbonaceous deposit recovered activity, the presence of O₂ suppressed carbonaceous deposit formation. The presence of H₂ under lean conditions had much less effect on catalyst activity than H₂ presence under rich conditions. Rich conditions with O₂ presence represented the most detrimental effect on catalyst activity.