Enhancement of the NH3-SCR catalytic activity of MnTiOx catalyst by the introduction of Sb

Abstract

Sb was used as the additive to enhance the NH3-SCR performance of MnTiOx catalyst. Experimental results revealed that MnSbTiOx-0.2 demonstrated outstanding NH3-SCR activity in a wide temperature window (100–400 ℃) and high resistance to SO2. Characterization results indicated the introduction of Sb into MnTiOx catalyst could improve the dispersity of active species and generate more surface acid sites, Mn4+ and surface adsorbed oxygen species. In situ DRIFT spectra proved that the presence of Sb in MnSbTiOx-0.2 catalyst could form new Brønsted acid sites, along with the increased surface Lewis acidity. The improved adsorption of NH3 and NOx species over MnSbTiOx-0.2 catalyst had a stimulating effect on the NH3-SCR reaction over it through Langmuir−Hinshelwood (L-H) route. Moreover, Sb species in MnSbTiOx-0.2 could improve the reactivities of ad-NH3 and ad-NOx species in SCR reaction. All these factors contributed to the excellent performance of MnSbTiOx-0.2 catalyst.