Efficient MnFe/Al2O3 catalyst for NH3-SCR of NO at low temperature: the influence of strong interactions between active components and the carrier

Abstract

Supported MnFeO_x catalysts have been prepared using Al₂O₃ as the substrate and were investigated for NH₃-SCR. The 20% MnFe/Al₂O₃ catalyst removed over 80% of NO_x with an N₂ selectivity exceeding 90% at temperatures between 80 and 340 °C. The results from the various characterization studies indicated that the increased activity of MnFe/Al₂O₃ catalysts can be primarily linked to the increased chemisorbed oxygen species and Fe³⁺ concentrations, greater reducibility, and higher adsorption capacity for NH₃. These characteristics are the outcome of the strong interaction, larger specific surface, and abundant acidic sites. Additionally, in situ DRIFTS analysis of the reaction mechanism revealed that the E–R and L–H mechanisms were responsible for the NH₃-SCR reaction over the 20% MnFe/Al₂O₃ catalyst.