The effect of Ce on the activity and alkali resistance of V2O5/TiO2 catalyst for the selective catalytic reduction (SCR) of NOx by NH3 has been investigated. It was found that the addition of Ce not only reduced the vanadium loading of V2O5/TiO2 but also enhanced its activity and alkali resistance. The NOx conversion over 0.5%V2O5-5%CeO2/TiO2 was much higher than that over 1%V2O5/TiO2 catalyst. Based on the catalyst characterization, the redox cycle (V4+ + Ce4+ <-> V5+ + Ce3+) can account for the excellent NH3-SCR catalytic performance of 0.5%V2O5-5%CeO2/TiO2 catalyst. In situ diffuse reflectance infrared transform spectroscopy (DRIFTS) measurements revealed that the role of Ce on the V2O5-CeO2/TiO2 catalyst was to contribute to the formation of NO2 and monodentate nitrate species, both of which were reactive intermediates for the NH3-SCR of NOx. (C) 2014 Elsevier B.V. All rights reserved.