The effect of carbon-NSR catalyst contact on the ability of the catalyst to store NOx is investigated. The catalysts used are model catalysts composed of Pt and/or Ba supported on Al2O3 (2%Pt/gamma-Al2O3, 20%BaO/gamma-Al2O3 and 2% Pt-20%BaO/gamma-Al2O3). It is shown that the presence of carbon black in the catalytic bed involves a decrease of the NOx storage capacity (NSC) of the catalysts. Participation of a direct reaction between carbon particles and NOx storage sites to form carbonate adsorbed species is proposed. However, the loss of NSC measured in the presence of carbon varies as a function of the catalyst composition. It is shown that the presence of platinum limits the influence of carbon-catalyst contact. The influence of the proximity between the storage sites, Pt sites and their contact with carbon is discussed. (C) 2012 Elsevier B. V. All rights reserved.