Effect of the Pt–Co interaction upon the SCR of NOx over PtCo mordenite Original Research Article

The selective catalytic reduction of NOx with CH4 in excess oxygen was studied over a series of mordenites containing either Co or Pt, or both. To ascertain the nature of the Pt promoting effect, mechanical mixtures and different combinations of the two-bed system made up of the monometallic mordenites were also investigated. To substantiate the role of the zeolite framework, mono and bimetallic alumina supported catalysts were tested. In all cases, the catalytic tests were run with and without water added to the feed stream. Temperature-programmed reduction of the different catalyst systems provided additional information concerning the nature of the Co–Pt interaction. The best formulation was obtained with a small addition of Pt to the Co mordenite, Co/Pt = 15. This mordenite has a performance similar to the best bimetallic zeolites reported in the literature. This study demonstrates that the best results are obtained when Co and Pt are in close vicinity in the mordenite framework.