The present work explored the effect of MnOx modification on the activity and adsorption of CuO/Ce0.67Zr0.33O2 catalyst for NO reduction by CO. XRD, Raman, UV, XPS, H-2-TPR, and in situ FT-IR were used to characterize these catalysts. Results suggested that the incorporation of copper and manganese species resulted in the lattice expansion and the decease of microstrain of ceria-zirconia, thus inducing the formation of oxygen vacancies. There was a strong interaction between surface copper, manganese, and the support via charge transfer. The addition of manganese species could promote the reduction of the resultant catalysts and assist copper oxide in changing the valence and the support in supplying oxygen. These reduction behaviors were dependent on the loading amounts of MnOx and the impregnation procedure. In addition, the introduction of MnOx cannot change the adsorption type of NO, but readily helped to activate the adsorbed NO species. As a result, these factors were responsible for the enhancement of activity and selectivity through MnOx modification. (C) 2010 Elsevier Inc. All rights reserved.