Synergistic reaction of NH3 selective catalytic reduction and CO oxidation on in-situ sulfated CoMn2O4/CeTiOx

The removal of NOₓ emissions from flue gas by NH 3 selective catalytic reduction (SCR) over catalysts has always been a challenge due to poisoning from the contained water and sulfur. This study demonstrates that rather than poisoning, the contained H 2 O and SO 2 can work positively through an in-situ sulfation process for CoMn 2 O 4 /CeTiOₓ (CMCT) catalysts, thus providing a synergistic effect for CO oxidation and NH 3 -SCR for improving the catalyst activity and selectivity. The obtained sulfated catalyst, achieves over 90 % conversion for NOₓ and about 100 % for CO with nearly 90 % N 2 selectivity at 225–350 °C. The mechanism studies are conducted and the enhanced effect for NH 3 -SCR is revealed from the formed Brønsted acid, surface sulfates, and the reactive oxygen species (O*) generated during CO oxidation. Furthermore, the function of CO adsorption is explored in separating reaction sites and suppressing excessive NH 3 oxidation for achieving high N 2 selectivity.