Effect of sulfur poisoning on the performance and active sites of Cu/SSZ-13 catalyst

This study focuses on exploring the impact of sulfur poisoning and regeneration on the performance and active sites of Cu/SSZ-13 catalyst. It was found that sulfured samples had obviously lower conversion than fresh samples below 350 degrees C, and thermal regeneration at 550 degrees C could not totally remove sulfate species. These catalysts were also comprehensively characterized by H-2-TPR, TPD, NH3-TPO, NO-TPO, and BET. SO2 and NH3 co-adsorbed on the Z(2)Cu sites to form ammonia sulfate species, however, they went through the two-step decomposition reaction during regeneration. SO2 interacted more tightly with ZCuOH to form copper bisulfite species. SO2 was oxidized by CuxOy species to further form sulfate species. Si-O(H)-Al bond could be sulfur poisoned when Cu species in the catalysts. Additionally, sulfated species could block pores, but not lead to structure collapse. Furthermore, in situ DRIFTS results illustrated that active sites and nitrates/nitrites storage capacity decreased after sulfur poisoning. (C) 2020 Elsevier Ltd. All rights reserved.