Design of co-symbiotic FexMnyO catalysts for NO reduction by CO†
A smooth spherical FexMnyO catalyst with different Fe contents was prepared by the solvent thermal method using ethylene glycol and the CO-SCR activity of the catalyst was tested to deeply explore the influence of metal Fe doping amount on the activity of the manganese-based catalyst. It was found that the addition of Fe species resulted in a strong synergistic symbiosis between the two-phase composite oxides. For the optimized Fe0.3Mn0.7O catalyst at 300 °C, the NO conversion rate and N2 selectivity reached 100% and 97.5%, respectively. The experimental results showed that the doping of FeOx could promote the reaction Fe2+ + Mn4+ → Fe3+ + Mn3+, which was beneficial to the generation of oxygen cavitation and reactive oxygen species. Moreover, the unique smooth spherical morphology of MnOx has a large specific surface area which fully provides the exposure opportunity for the active species FeOx and improves the catalytic activity of the catalyst. In addition, according to the results of in situ infrared experiments, we propose a reasonable CO-SCR model reaction mechanism.