Fe–Mn–Ce/ceramic powder composite catalyst for highly volatile elemental mercury removal in simulated coal-fired flue gas

The Fe–Mn–Ce/CP catalyst prepared by the incipient-wetness impregnation method was investigated for elemental mercury (Hg0) removal in simulated coal-fired flue gas. The incorporation of Fe could remarkably enhance the SO2-resistance of Fe–Mn–Ce/CP catalyst at low temperature, and the existence of water vapor had negative impact on Hg0 removal efficiency. More than 95% of Hg0 could be removed at 100 °C under the conditions of 60 ppm HCl, 3% O2 (v/v), 5% H2O (v/v) and 400 ppm SO2. Hg-TPD results indicated that Hg0 adsorption amount decreased after the addition of H2O or SO2. The XPS results revealed that the incorporation of Fe could enhance the contents of high valence Mnx+ (i.e., Mn3+/Mn4+) and Ce3+ species in the composite catalysts, which are favorable for the oxidation process of elemental mercury. The surface characteristics were not the primary factor determining the catalytic activity. Overall, the catalytic performance of the Fe–Mn–Ce/CP catalyst was closely related to the Fe3+ state, high ratios of (Mn4+ + Mn3+)/Mn2+ and high content of not fully coordinated cerium species.