Deactivation mechanism of SO2 on Cu/SAPO-34 NH3-SCR catalysts: structure and active Cu2+Electronic supplementary information (ESI) available: Some related figures are shown in the ESI. See DOI: 10.1039/c4cy01129e

The deactivation mechanism of Cu/SAPO-34 ammonia selective catalytic reduction catalysts (NH 3 -SCR) by SO 2 poisoning has been systematically investigated using a range of analytical techniques in order to study the influence on both the zeolitic framework and the active Cu 2+ ions. The different sulfate samples were obtained by SO 2 poisoning over Cu/SAPO-34 NH 3 -SCR catalysts as a function of time and concentration in the feed. The obtained results reveal that the SO 2 poisoning could seriously decrease NO conversion during the whole temperature range (100-500 °C). The XRF results shows that there is almost no sulfur existing on the SAPO-34 support. The ex situ DRIFTS and BET results reveal that SO 2 poisoning has a less-pronounced effect on its framework structure. The TPR and EPR results demonstrate that SO 2 poisoning has a significant influence on the coordination environment and the content of the active isolated Cu 2+ species. The kinetic results demonstrate that the SO 2 poisoning does not influence the apparent activation energy ( E a ) of the NH 3 -SCR reaction over Cu/SAPO-34 catalysts. The decline of the NH 3 -SCR activity is due to the reduction of the number of isolated Cu 2+ ions. The deactivation mechanism of structure and active site for Cu/SAPO-34 catalysts by SO 2 poisoning has been investigated using a range of analytical techniques.