The objective of this study was to evaluate model Pt catalysts supported on ceria-zirconia, with and without barium, for the reduction of NO by CO on stoichiometric conditions. The supports were named CZ and CZBa. The supports impregnated with Pt were named PtCZ and PtCZBa. The presence of Ba improved the reducibility of the catalysts, which probably contributed to ameliorate the catalytic activity. Lightoff curves showed two peaks of N2O: one at low temperature (250 degrees C) and another at high temperature (425 degrees C). The catalysts with Pt only reached significant activity and selectivity to N-2 above 450 degrees C. According to the literature, the reaction mechanism changes depending on the temperature. At low temperature, the mechanism of N2O production probably occurs by redox reactions with the metal promoting the creation of the oxygen vacancies over the CZ support by CO activation. Barium presence improve the activity and the N-2 selectivity. (C) 2013 Elsevier B.V. All rights reserved.