The simultaneous presence of sodium and copper on novel Na/Cu/CeO 2 and Na/Cu/CeY catalysts resulted in a dramatic increase in the catalytic adsorption of NO. Copper catalyzes the oxidation of NO to NO 2, which is further adsorbed by the sodium phase. The intimate contact of both phases favors the formation of nitrates on the surface. The cooperative effect between the copper and sodium phases increases the reduction temperature of copper. It was found that the addition of copper induced a stabilizing effect on the surface area of the catalysts. © 2012 Elsevier B.V.