MnCe/GAC-CNTs catalyst with high activity, SO2 and H2O tolerance for low-temperature NH3-SCR

Abstract

SO2 and H2O tolerance is a crucial issue for low-temperature selective catalytic reduction of NO with NH3 (NH3-SCR) in practical application. In the present work, MnCe/GAC-CNTs catalysts were prepared and showed high activity, SO2 and H2O tolerance for low-temperature NH3-SCR. The catalysts were characterized by SBET, XPS, XRD, NH3−TPD, and DRIFTs. MnCe/GAC-CNTs exhibited higher catalytic activity and H2O + SO2 tolerance than CeO2/GAC-CNTs due to electron transfer between Ce and Mn species (Ce4+ + Mn3+ ↔ Ce3+ + Mn4+) accompanied with higher proportion Ce3+, and the improvement of surface acidity concentration and strength. Besides, Mn addition inhibited the oxygen inhibitory effect, enhanced the adsorption of NO, and increased the proportion diameter, which were beneficial to SO2/H2O resistance. Furthermore, the presence of Mn suppressed the formation of hydroxyl group, inhibited the adsorption of SO2, ultimately limited electron transfer between SO2 and Ce4+, which led to high SO2 tolerance of the MnCe/GAC–CNTs catalyst. Therefore, MnCe/GAC-CNTs catalyst with high deNOx performance and SO2/H2O tolerance, showed the potential of practical low-temperature deNOx application.