Ultra-low temperature selective catalytic reduction of NOx into N2 by micron spherical CeMnOx in high-humidity atmospheres containing SO2

Abstract

The solvothermal synthesis of optimized micron-sized spherical CeMnO-350 yields remarkable results in ultra-low temperature NH-SCR of NO, with over 91 % NO conversion achieved between 59 and 255 ℃. Notably, under 5 vol% HO and 50 ppm SO, the CeMnO maintains NO conversion >99 % at 127 ℃ for extended periods, surpassing current ultra-low temperature deNO standards. This superior performance is attributed to the material's unique characteristics: the regular and porous surface morphology enhances exposure to active sites, particularly MnO(112) facets crucial for ultra-low temperature deNO, while the rough and loose surface and high MnO(222) exposure mitigate water vapor and SO poisoning. Furthermore, the thermal storage effect of the MnO/MnO system within CeMnO facilitates rapid thermal dissipation and ammonium sulfite decomposition. This process is further augmented by the pores, which aid in the confinement of deNO reaction heat and facilitate the flushing of flowing flue gas, thereby impeding the formation of ammonium bisulfate.