Enhanced performance and SO2 tolerance of Ce modified TiO2 supported Mn Sm catalyst for synergetic removal of Hg0 and NO from flue gas

By adjusting the redox property and surface acidity/basicity, the Ce modified TiO2 supported MnSm catalyst with high activity and good anti‑sulfur ability was developed for synergetic removal of Hg0 and NO. MnSm/TiCe achieved a simultaneous removal efficiency of NO and Hg0 of 98.7%, 90.4% and 83.7%, 76.8% (with presence of 200 ppm SO2 and 3% H2O) at 200 °C in simulated flue gas, respectively. Characterization results indicated that MnSm/TiCe possessed well-dispersed active components, increased Mn4+concentration and Lewis acid sites and enhanced reducibility and oxygen storage capacity, which were in favor of the catalyst performance. Abundant active nitrogenous species derived from adsorbed NO contributed to Hg0 oxidation. The in-situ DRIFTS experiments manifested that the reaction of gaseous NO with NH2 on Lewis acid sites via Eley-Rideal mechanism was the main route for NH3-SCR. Due to strong basicity, Sm species served as a SO2 trap agent, which protected the Mn active sites against SO2 poisoning and inhibited the formation of sulfates, thus strengthening the SO2 tolerance of catalyst. Regeneration and stability evaluation tests indicated that MnSm/TiCe might be a promising catalyst that can be applied to the simultaneous removal of Hg0 and NO.