High-surface area nanosized CuO-CeO2 catalysts were prepared by a surfactant-templated method and tested for CO oxidation. The catalysts were characterized by XRD, TEM, N-2 sorption, H-2-TPR, and CO-TPR. The surfactant method can be used for preparing CuO-CeO2 mixed oxides with a crystallite size of about 5 nm. The highest BET surface area of the catalysts was 215 m(2) g(-1), achieved over a 3.3% CuO content catalyst. XRD results indicated that the absence of a CuO phase with < 12% CuO content may partially incorporate in the CeO2 lattice to form CuxCe1-xO2-delta solid solution, whereas a higher CuO content causes the formation of bulk CuO. These high-surface area nanosized catalysts were found to be very active for CO oxidation reaction; the lowest T-90 was 80 degrees C, achieved over a 12.0% CuO content catalyst. In addition, the CuO-CeO2 catalysts also show high catalytic activity for selective oxidation of CO in excess H-2 at relatively low temperature. H-2-TPR results reveal three reduction peaks for these catalysts, which could be attributed to reduction of the highly dispersed CuO, the Cu2+ in the CeO2 lattice, and the bulk CuO. Removal of the finely dispersed CuO in the catalyst by acid treatment resulted in a decline in catalytic activity for CO oxidation, indicating that the finely dispersed CuO species are the active sites for the reaction. (c) 2006 Elsevier Inc. All rights reserved.