Effect of SO2 on NH3 oxidation over a Cu-SAPO-34 SCR catalystElectronic supplementary information (ESI) available. See DOI: 10.1039/c5cy02212f

The impact of SO 2 on NH 3 oxidation, an undesired side reaction that can occur during NH 3 -SCR, was studied using Cu-SAPO-34. Based on kinetic analysis, monomeric Cu ++ was active toward NH 3 oxidation. In terms of the SO 2 effect, significant loss in NH 3 oxidation activity was observed at temperatures below 350 °C. However, at higher temperatures, SO 2 had no significant effect on NH 3 oxidation, which corresponds to the lack of an observed effect on SCR performance. Temperature-programmed-desorption (TPD) data obtained after NH 3 and SO 2 exposures demonstrate that SO 2 inhibited monomeric copper NH 3 oxidation activity through formation of ammonium sulfate, whose formation was catalyzed by the Cu. The monomeric copper regained NH 3 oxidation activity after ammonium sulfate decomposed. The impact of SO 2 on NH 3 oxidation, an undesired side reaction that can occur during NH 3 -SCR, was studied using Cu-SAPO-34.