Mn-Co Binary Oxides For Low-Temperature Catalytic Oxidation Of No: Effect Of So2 And Regeneration

BACKGROUND In this paper, Mn-Co binary oxides prepared by an (NH4)(2)CO3-assisted co-precipitation method were used for the catalytic oxidation of NO at low temperatures. RESULTS Experimental results showed that the Mn-Co binary catalysts prepared with manganese acetate and cobalt nitrate exhibited the highest oxidation activity, obtaining a NO conversion of 76% at 200 degrees C and 80% at 250 degrees C. The passivation effect of SO2 was found to be irreversible in the examination of the resistance to SO2 or/and H2O(g). Furthermore, characterization by X-ray Photoelectron Spectroscopy (XPS), Fourier Transform infrared spectroscopy (FTIR), and in situ Diffuse Reflectance Infrared Fourier Transform spectroscopy (DRIFTs) revealed that the passivation effect was due to the bidentate and surface or bulk-like sulfates generated on the surface of the catalyst. CONCLUSION The analysis of intermediate species during the in situ DRIFTs characterization revealed that these sulfate species competed with nitrate/nitrite species for adsorption and affected the activity. Moreover, the poisoned catalysts could be regenerated to remove the majority of the bidentate and surface or bulk-like sulfates from the surface and maintain the excellent NO catalytic oxidation activity. (c) 2021 Society of Chemical Industry (SCI).