Abstract:

In order to assist the industry in achieving the goal of emission peak and carbon neutrality,focusing on the syner-gistic removal of oxynitrides（NO_x） and carbon monoxide（CO） in low-temperature flue gas,inorganic salts of cerium（Ce） and manganese（Mn） were used as precursors,then Mn-based ammonia selective catalytic reduction（NH₃-SCR）/CO oxidation bi-functional nanocatalysts modified by Ce were prepared by co-precipitation,mechanical ball milling,solution combustion and sol-gel methods.The catalytic performance was evaluated on a fixed bed reactor with online mass spectrometry/chromato-graphy system.The structure of Ce-MnO_x nanocatalysts were characterized and analyzed by X-ray diffraction,N₂-physisorp-tion and other techniques.The results showed that the catalyst prepared by the reverse co-precipitation method had the best performance for synergistic removal of NO_x and CO.At a high space velocity of 100 000 mL/（g·h）,more than 85% of CO purification can be achieved above 140 ℃,more than 80% of NO_x in the gas can be removed above 100 ℃,and only a slight performance degradation occurs after 20 h of operation.The active component was CeMnO_x with a high specific surface area above 100 m²/g,which could adsorb more gas for reaction and showed excellent catalytic performance.

Key words: low-temperature selective catalytic reduction, catalytic oxidation of carbon monoxide, rare earth elements, man-ganese oxide