MnO -CeO2 supported on Cu-SSZ-13: A novel SCR catalyst in a wide temperature range

Abstract A novel Mn-Ce/Cu-SSZ-13 catalyst was synthesized for the selective catalytic reduction of NO with NH 3 (NH 3 -SCR) over a wide temperature range. The NO x conversions of this catalyst were above 90% from 125 °C to 450 °C. The catalyst also possessed good H 2 O and SO 2 resistances at 300 °C and possessed higher activities than Cu-SSZ-13 at 80 °C to175 °C and Mn-Ce at above 200 °C. TPD and in situ DRIFTS analyses showed that bridging nitrate groups on Cu-SSZ-13 could not participate in the SCR reaction. Moreover, NH 3 was easily adsorbed to form NH 4 NO 3 , which encased the surface of the catalyst, thereby blocking the pores and deactivating the active sites. However, for Mn-Ce/Cu-SSZ-13, the bridging nitrates were adsorbed onto the surface and then converted to monodentate nitrates, which acted as the active species for the SCR reaction at low temperature. This phenomenon might be the primary reason for the enhanced SCR performance of Mn-Ce/Cu-SSZ-13 compared with Cu-SSZ-13 at low temperature.