MnOx-CeO2-Al2O3 mixed oxides were prepared by impregnating manganese acetate and cerium nitrate on alumina powders using the sol-gel method. The thermal stabilities of MnOx-CeO2 and Al2O3-modified mixed oxides were evaluated by treating at 800 degrees C in dry air flow for 20h. The introduction of Al2O3 markedly increases the textural stability of the catalyst with a relatively high dispersion of MnOx and CeO2, remaining a strong synergistic effect between these two oxides. The NO oxidation activity of the ternary oxides experiences a smaller loss after high-temperature calcination, and a low soot oxidation temperature is attained in the presence of NO. (C) 2011 Elsevier B.V. All rights reserved.