Insight into SO2 poisoning and regeneration of one-pot synthesized Cu-SSZ-13 catalyst for selective reduction of NOx by NH3

[Display omitted] The effects of SO2 on an one-pot synthesized Cu-SSZ-13 catalyst for selective reduction of NOx by NH3 were examined. The addition of SO2 inhibited NOx conversion significantly below 300 °C, while no effect on NOx conversion was observed above 300 °C. TGA, TPD, and XPS results showed that the deactivation was caused by the formation of (NH4)2SO4, SO2 chemisorption on the isolated Cu2+ ion sites, as well as the formation of CuSO4-like species. Among them, the site-blocking effect of (NH4)2SO4 on Cu2+ was the primary reason for deactivation. Fortunately, 89% of deNOx activity of the poisoned catalyst was recovered after thermal treatment at 500 °C in air, where (NH4)2SO4 was completely decomposed. The activity was further recovered with regeneration temperature increasing to 600 °C, removing the adsorbed SO2 on the Cu2+ sites. The regeneration at 600 °C could not recover the activity completely, because of the high stability of CuSO4-like species.