Low-temperature selective catalytic reduction of NOx with NH3 over a manganese and cerium oxide/graphene composite prepared by a hydrothermal method

Abstract

MnO_x–CeO₂/graphene (MnO_x–CeO₂/GR) catalysts prepared by a hydrothermal method with different mass ratios of graphene (0–0.45 wt%) were investigated for the low-temperature selective catalytic reduction (SCR) of NO_x with NH₃. The as-prepared catalysts have been characterized systematically to elucidate their morphological structure and surface properties by XRD, SEM, TEM, BET, XPS, H₂-TPR, NH₃-TPD and FT-TR. It was found that the environmentally benign MnO_x–CeO₂/GR (0.3 wt%) catalyst exhibited excellent NH₃-SCR activity and strong resistance against H₂O and SO₂, which is very competitive for application in controlling NO_x emission from flue gas. On the basis of the catalyst characterization, the high specific surface areas, the uniform distribution of active sites, and the interaction of manganese and cerium oxide species played key roles in the excellent catalytic performance of MnO_x–CeO₂/GR and resulted in improved SO₂ tolerance.