High-surface area CuO–CeO2 catalysts prepared by a surfactant-templated method for low-temperature CO oxidation

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, N2 sorption, H2-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 m2 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−δ 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 T90 was 80 °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 H2 at relatively low temperature. H2-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.