Preliminary studies on a series of nanocomposite BaO-FeZSM-5 materials have been carried out to determine the feasibility of combining NOx trapping and SCR-NH3 reactions to develop a system that might be applicable to reducing NOx emissions from diesel-powered vehicles. The materials are analysed for SCR-NH3 and SCR-urea reactivity, their NOx trapping and NH3 trapping capacities are probed using temperature programmed desorption (TPD) and the activities of the catalysts for promoting the NH3 ads + NO/O-2 -> N-2 and NOx ads + NH3 -> N-2 reactions are studied using temperature programmed surface reaction (TPSR). (c) 2006 Elsevier B.V. All rights reserved.