Mn-Ce/ZSM-5 catalyst prepared in an aqueous phase at 423 K exhibits a broad temperature window (517-823 K) for high NO conversions (75-100%) in the process of selective catalytic reduction (SCR) by NH3 even in the presence of H2O and SO2. Both the zeolite matrix and the over-exchanged amounts of manganese and cerium contribute to obtain a complex structure that owns microporous-mesoporous characteristics and specific surface properties. (c) 2006 Elsevier B.V. All rights reserved.