Roles of palladium and platinum in the selective catalytic reduction of nitrogen oxides by methane on palladium–platinum-loaded sulfated zirconia

The selective reduction of nitrogen oxides by methane on Pd–Pt/sulfated zirconia (SZ) was investigated. The activity of Pd–Pt/SZ was noticeably higher than that of either Pd/SZ or Pt/SZ. The cooperative effect of Pd and Pt, Pd acting as sites for the reaction of NO2 with methane and Pt catalyzing NO oxidation to NO2, was suggested. The addition of Pt to Pd/MOR showed a similar improvement, but the effect was much more prominent for Pd/SZ.