The purpose of this study is to observe the effects of H-2 generation by a reforming catalyst (Cu30/gamma-Al2O3) with various additives, so as to improve the durability of the combined system of reforming catalyst (RC)+LNT. Under both fresh and hydrothermal aging conditions, the H-2 yields of the Cu29CeO(2)1/gamma-Al2O3 catalyst were the highest among the reforming catalysts prepared by the sol-gel method. Even though the H-2 yield obtained using the DME reforming reaction of the exhaust gases of DME vehicles has the advantage of using the heat source and water in the exhaust gas, the existence of NO, CO2 and O-2 in the exhaust gases is disadvantageous to the DME reforming reaction. The NOx conversion of the combined system of RC (Cu29CeO(2)1/gamma-Al2O3)+LNT was higher than that of the LNT alone. This shows that the H-2 generated by the reforming reaction using the exhaust gases of the DME engine is a more effective reductant. Therefore, in order to effectively improve the NOx conversion, the combined system of RC+LNT is needed as an after-treatment system for DME vehicles. (C) 2012 Elsevier B.V. All rights reserved.