Promotional effects of Nb5+ and Fe3+ co-doping on catalytic performance and SO2 resistance of MnOx-CeO2 low-temperature denitration catalyst.

ABSTRACT

As we know, SO2 can cause MnOx-CeO2 (MnCeOx) catalyst poisoning, which seriously shortens the service life of the catalyst. Therefore, to enhance the catalytic activity and SO2 tolerance of MnCeOx catalyst, we modified it by Nb5+ and Fe3+ co-doping. And the physical and chemical properties were characterized. These results illustrate that the Nb5+ and Fe3+ co-doping can optimally improve the denitration activity and N2 selectivity of MnCeOx catalyst at low temperature by improving its surface acidity, surface adsorbed oxygen as well as electronic interaction. What's more, NbOx-FeOx-MnOx-CeO2 (NbFeMnCeOx) catalyst possesses an excellent SO2 resistance due to less SO2 being adsorbed and the ammonium bisulfate (ABS) formed on its surface tends to decompose, as well as fewer sulfate species formed on its surface. Finally, the possible mechanism that Nb5+ and Fe3+ co-doping enhances the SO2 poisoning resistance of MnCeOx catalyst is proposed.