Highly dispersed MnO_{: X} -FeO_x supported by silicalite-1 for the selective catalytic reduction of NO_x with NH₃at low temperatures

A silicalite-1-based catalyst with highly dispersed manganese and iron oxides was synthesized by the wet impregnation method for the selective catalytic reduction (SCR) of NOx with NH3 at low temperatures. The optimized catalyst demonstrated over 90% NOx conversion efficiency between 135 and 270 °C with a space velocity of 35 000 h-1, which can be attributed to the well-developed porous structure of silicalite-1 and the synergistic effects between silicalite-1 and supported metal oxide active sites. In addition, the porous structure and the addition of FeOx greatly promoted the dispersion of MnOx nanoparticles, which further improves the efficiency of SCR. Moreover, the reaction route for the NH3-SCR reaction was further investigated by in situ diffuse reflectance infrared Fourier transform spectroscopy (in situ DRIFTS). The corresponding test results indicate that the reaction route follows both Eley-Rideal (E-R) and Langmuir-Hinshelwood (L-H) mechanisms.