A series of highly effective CuCexCo1-xOy catalysts with diverse surface/interface structures were synthesized and applied to NO reduction by CO from 100 to 400 degrees C. The CuCe0.2Co0.8Oy catalyst exhibited superior catalytic performance, achieving 100% NO reduction at 175 degrees C. The structural and physicochemical properties and the intermediate species were systematically characterized. The results indicated that the surface dispersity of CuO species, the generation of low-oxidation-state metal species (Cu+ and Co2+) and surface oxygen vacancies (SOVs) were greatly enhanced due to stronger interaction between highly dispersed CuO species and supports, which favors for the enhancement of consequent redox properties and the regeneration of SOVs and low-oxidation-state metal ions during NO reduction by CO. The in situ FT-IR (Fourier transform infrared) results illustrated that the adsorption bands of CO2 and N2O on the CuCe0.2Co0.8Oy surface could emerge at lower temperatures, revealing that the CO adsorption/conversion and NO dissociation were significantly promoted by Ce modification.