Promotional mechanism of activity of CeEuMnOxternary oxide for low temperature SCR of NOx

Due to strong synergistic effect of the elements, a series of XEuMnOxternary oxides (X = Ce, Ni, Co, Sb, Sn, Mo) were synthesized by one-pot co-precipitation method, and composite components were identified and optimized to maintain high activity and superior SO2and H2O endurance in selective catalytic reduction of NOxwith NH3(NH3-SCR). NOxconversion of CeEuMnOxternary oxide catalysts attains more than 90% at 100–250 °C, and finally achieves 74% under existence of 50 × 10−6SO2and 10 vol% H2O at 230 °C. The facile electron transfer through redox cycle of Mn3+ + Ce4+↔ Mn4+ + Ce3+and enhanced oxygen mobility can promote formation of more Mn species in high oxidation state and chemisorbed oxygen, accelerating oxidation of NO and the adsorbed NO2formed can facilitate “fast SCR” reaction to improve low-temperature activity. In situdiffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) study reveals that addition of Ce to EuMnOxcatalyst boosts adsorption of NH3and NOxspecies. NH3species are activated as crucial intermediate (NH2) to promote NH3-SCR reaction. This research provides a novel material for practical deNOxapplication of stationary source combustion flue gas in the future.