Improved Low‐Temperature Activity and H2O Resistance of Fe‐Doped Mn−Eu Catalysts for NO Removal by NH3−SCR

Novel Mn-Eu-Fe catalysts were prepared via co-precipitation method for NOx removal by selective catalytic reduction with NH3 (NH3-SCR). The Mn-Eu-Fe(1)-500 catalyst possessed the highest level of low-temperature activity, giving 98 % NO conversion at 100 degrees C. This catalyst also exhibited excellent H2O resistance capacity, even at a high gas hourly space velocity (GHSV) of 75,000 h(-1). The NO conversion still maintained at approximately 90 % in the presence of 15 % H2O at 230 degrees C after 50 h, and the adverse effects of H2O could be quickly eliminated after the removal of H2O. Detailed characterization and analysis indicated that strong interactions among Mn, Eu and Fe resulted in the excellent low-temperature SCR activity and H2O resistance of the Mn-Eu-Fe(1)-500 catalyst. The strong interactions lead to larger specific surface area, higher concentrations of Mn4+, Fe3+ and O-alpha; improved redox properties, increased acid sites and acid strength, and more adsorption amounts of NO/NH3 in the presence of H2O. The Mn-Eu-Fe(1)-500 catalyst is a potential future catalyst for low-temperature NOx removal derived from high-H2O-content flue gases of natural gas combustion.