Enhanced Low Temperature NO Reduction Performance via MnOx-Fe2O3/Vermiculite Monolithic Honeycomb Catalysts.

Selective catalytic reduction of NO_x by ammonia (NH3-SCR) was the most efficient and economic technology for De-NO_x applications. Therefore, a series of MnO_x/vermiculite (VMT) and MnO_x-Fe₂O₃/VMT catalysts were prepared by an impregnation method for the selective catalytic reduction (SCR) of nitrogen oxides (NO_x). The MnO_x-Fe₂O₃/VMT catalysts provided an excellent NO conversion of 96.5% at 200 °C with a gas hourly space velocity (GHSV) of 30,000 h^-1 and an NO concentration of 500 ppm. X-ray photoelectron spectroscopy results indicated that the Mn and Fe oxides of the MnO_x-Fe₂O₃/VMT catalyst were mainly composed of MnO2 and Fe₂O₃. However, theMnO2 and Fe₂O₃ components were well dispersed because no discernibleMnO2 and Fe₂O₃ phases were observed in X-ray powder diffraction spectra. Corresponding MnO_x-Fe₂O₃/VMT monolithic honeycomb catalysts (MHCs) were prepared by an extrusion method, and theMHCs achieved excellent SCR activity at low temperature, with an NO conversion greater than 98.6% at 150 °C and a GHSV of 4000 h^-1. In particular, theMNO_x-Fe₂O₃/VMTMHCs provided a good SCR activity at roomtemperature (20 °C), with an NO conversion of 62.2% (GHSV = 1000 h^-1). In addition, the NO reduction performance of theMNO_x-Fe₂O₃/VMTMHCs also demonstrated an excellent SO2 resistance. [ABSTRACT FROM AUTHOR]