Catalytic Reduction of NO and N2O to N2 in the Presence of O2, C3H6, SO2, and H2O

The reduction of NO and N2O to N2 under the same reaction conditions was studied. When both NO and N2O coexisted in the feed, the two gases were reduced at different temperatures over Rh/- or Ru/Al2O3. NO was reduced over In/Al2O3 and N2O over Ru/- or Rh/Al2O3 at the same temperature range. Bimetallic catalysts consisting of both In and Ru sites were not efficient for the simultaneous NO and N2O reduction because C3H6 was oxidized over the Ru sites. A two-layered catalytic bed made of In/Al2O3 located close to the feed inlet and Ru/Al2O3 located close to the reactor exit was used to efficiently reduce (more than 80% conversion) both NO and N2O at 450 °C. The performance of the same catalytic system was tested by adding both H2O and SO2 in the feed. These gases caused a moderate inhibition in the activity, thus shifting the conversion vs temperature curves to higher temperatures and lowering the conversion to N2.