Low temperature SCR reaction over Nano-Structured Fe-Mn Oxides: Characterization, performance, and kinetic study.

Fe-Mn oxides was prepared by thermal activation of Mn-rich limonite at different temperatures, and then developed as catalysts for low-temperature NH 3 -SCR. The obtained samples were characterized by XRD, XRF, TEM, XPS, BET, H 2 -TPR, NH 3 -TPD, NH 3 -SCR model reaction and in situ DRIFTS. The results indicated that Fe-Mn oxides catalyst derived from the thermal treatment at 300 °C (H300) exhibited an excellent NO conversion which was higher than 90% at a temperature range from 130 to 300 °C. The large surface area (95.9 m 2 /g), large amount of acid sites, suitable reduction behavior, and abundant surface hydroxyl positively responsed to the excellent performance of H300 for NH 3 -SCR. The results of in situ DRIFTS and kinetic study demonstrated that when the SCR reaction temperature reached to 100 °C, both the Eley–Rideal mechanism and the Langmuir-Hinshelwood mechanism might happen over H300. However, the Langmuir-Hinshelwood mechanism could be approximately neglected at higher reaction temperatures. This study favors the understanding of NH 3 -SCR mechanism of the prepared provides Fe-Mn oxides and explores new application field for Mn-rich limonite in low-temperature NH 3 -SCR. [ABSTRACT FROM AUTHOR]