Experimental and DFT study of the adsorption and activation of NH3 and NO on Mn-based spinels supported on TiO2 catalysts for SCR of NOx

Abstract

CuMn2O4 and NiMn2O4 spinels supported on TiO2 were prepared by the impregnation method, and their efficiencies of selective catalytic reduction (SCR) of NOx with NH3 in the simulated flue gas were researched. The two kinds of catalysts showed high NH3-SCR activity for NOx removal over a range of temperature (353–453 K). According to the in situ diffuse reflectance infrared transform spectroscopy (in situ DRIFTS) test, a larger quantity of adsorbed NH3 was detected for CuMn2O4 when NH3 was introduced, and NiMn2O4 provided a larger adsorption amount of NO when NO was introduced. Meanwhile, the corresponding slab models were constructed by density functional theory (DFT) calculations to investigate the adsorption of NH3 and NO molecules. The DFT calculations of NO adsorption were in agreement with the results that were observed by the experiments.