Insight into Platinum Poisoning Effect on Cu-SSZ-13 in Selective Catalytic Reduction of NOx with NH3

Platinum’s (Pt) poisoning effect on Cu-SSZ-13 and its regeneration were investigated. The Pt enhanced the parallel reactions, such as NH3 oxidation and NO oxidation reactions, which decreased the deNOx activities. In the temperature range below 330 °C, the deactivation of Cu-SSZ-13 by Pt poisoning was primarily caused by the overconsumption of NH3, due to the enhanced NH3-selective oxidation reaction, while the formation of NOx in NH3 oxidation and NO oxidation into NO2 further aggravated the degradation when the temperature was above 460 °C. The non-selective NH3 oxidation and non-selective NOx catalytic reduction reactions resulted in increased N2O formation over Pt-doped samples. The transformation of Pt0 into PtOx after hydrothermal aging recovered the deNOx activities of the Pt-poisoned samples.