Abstract: The reduction of NO by activated carbon over a Cu-K-O mixed oxide catalyst was investigated. We found that the addition of K to CuO obviously improved its catalytic performance and stability, and the optimum Cu/K weight ratio is 2. Characterization by X-ray photoelectron spectroscopy, X-ray diffraction, and temperature-programmed desorption shows that the presence of K can promote the reaction between the surface carbon active sites and the surface oxygen species to form CO₂ by a synergetic effect between Cu and K. Additionally, a higher surface concentration of Cu²⁺ is retained, which favors the Cu²⁺/Cu⁺ reduction cycle on the active sites.

Key words: potassium, copper oxide, activated carbon, nitrogen monoxide, selective catalytic reduction