AVS 45th International Symposium
    Surface Science Division Tuesday Sessions
       Session SS2-TuM

Paper SS2-TuM11
An Investigation of the NO@sub x@ Storage Mechanism

Tuesday, November 3, 1998, 11:40 am, Room 309

Session: Noble Metal Catalysis
Presenter: M. Skoglundh, Chalmers University of Technology, Sweden
Authors: M. Skoglundh, Chalmers University of Technology, Sweden
H. Persson, Chalmers University of Technology, Sweden
E. Fridell, Chalmers University of Technology, Sweden
P. Engström, Chalmers University of Technology, Sweden
S. Ljungström, Chalmers University of Technology, Sweden
Correspondent: Click to Email
In order to reduce nitrogen oxides (NO@sub x@) from lean burn vehicles, NO@sub x@ storage catalysts are used. The key idea is to first store NO@sub x@ in the catalysts during lean conditions (oxygen in excess) and then the NO@sub x@ is released and reduced during short periods of fuel rich conditions. In the present study we systematically investigate the sequence of mechanistic elementary steps in the NOx storage cycle, by using different experimental techniques in combination with theoretical modelling. As a model system we have used a NO@sub x@ storage catalyst containing Pt, @gamma@-Al@sub 2@O@sub 3@ and BaO as the storage component. Our results suggest that an intermediate peroxide step (BaO@sub 2@) is essential for storing NO@sub x@ as Ba(NO@sub 3@)@sub 2@. Furthermore, the relative importance of direct NO@sub x@ storage via gas phase or NO@sub x@ storage via Pt spillover is discussed.