Effect of the Pt-Co interaction upon the SCR of NOx over PtCo mordenite

The selective catalytic reduction of NOx with CH4 in excess oxygen was stud ied over a series of mordenites containing either Co or Pt, or both. To asc ertain the nature of the Pt promoting effect, mechanical mixtures and diffe rent combinations of the two-bed system made up of the monometallic mordeni tes were also investigated. To substantiate the role of the zeolite framewo rk, mono and bimetallic alumina supported catalysts were tested. In all eas es, the catalytic tests were run with acid 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 interact ion. The best formulation was obtained with a small addition of Pt to the C o mordenite, Co/Pt = 15. This mordenite has a performance similar to the be st 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. (C) 2000 Elsevier Science B.V. All rights reserved .