Regeneration of a model NOX storage and reduction (NSR) catalyst using hydrocarbons. H-2, or CO as reducing agents was investigated. As previously shown, at low temperature, 200 degrees C. H-2 proved best, while both CO and hydrocarbons were found to poison Pt sites. At 250 degrees C, again H-2 was better but the decreased performance with CO and hydrocarbons was also due to slow kinetics and not solely as a result of Pt site poisoning. At T >= 300 degrees C, hydrocarbons were found to regenerate the catalyst as efficiently as CO and H-2. Hydrocarbon steam reforming experiments were performed to investigate the improved performance at T >= 300 degrees C. Steam reforming did not occur with either dodecane or m-xylene below 450 degrees C. Additionally, although propylene steam reforming occurred at 375 degrees C, the small amount of H-2 formed was insufficient for steam reforming to be the sole reason for improved regeneration. TPR experiments show that propylene was activated on the catalyst at T >= 217 degrees C and, under the conditions examined, the complete reduction of NO by propylene was achieved at 287 degrees C. Furthermore, propylene was observed to reduce surface chemisorbed NOX species at T > 200 degrees C, with high rates by 264 degrees C, with this activity ultimately resulting in the comparable performance with either CO or H-2 at similar temperatures during NOX cycling experiments. (C) 2010 Elsevier B.V. All rights reserved.