Insights into the structure-activity relationships of highly efficient CuCe oxides for the low temperature CO oxidation and CO-SCR

A series of Cu-doped Ce-based mixed metal oxide catalysts were prepared by the simplest impregnation method for CO oxidation and CO selective reduction of NO x (CO-SCR), respectively. Among them, 10Cu/CeO 2 catalyst showed excellent catalytic activity and stability in both reactions. The catalysts were characterized by XRD, BET, SEM, TEM, XPS, H 2 -TPR, Raman, O 2 -TPD and in-situ DRIFTS. The results show that the preferential exposure of the (111) crystal plane of CeO 2 is beneficial to the dispersion of Cu species. The introduced Cu enters the surface or lattice of CeO 2 , exposeing more catalyst active sites, which improves the catalyst reducibility and activity. In addition, the introduction of Cu into Ce-based catalyst also increases the types of active oxygen on the catalyst surface, improves the mobility of oxygen, and thus enhances the activity of the catalyst. The in-situ DRIFTS analysis shows that CO oxidation follows the M − K mechanism with Cu + as the core species, while CO-SCR follows the E-R mechanism at low temperature (50–150 °C) and the L-H mechanism at high temperature (200–400 °C). These results show that CuCeO 2 bifunctional catalyst can simultaneously meet the requirements of CO oxidation and CO-SCR reaction, which is of great significance for environmental governance. • Cu doping exhibits excellent activity in CO oxidation and CO-SCR. • Strong metallic interactions are exhibited between Cu and the support CeO 2 . • Cu + species is an important transition state in the two reaction processes. • Two possible reaction mechanisms were proposed based on in situ DRIFT study.