N-doped graphene and TiO2 supported manganese and cerium oxides on low-temperature selective catalytic reduction of NOx with NH3

Abstract

Abstract A series of N-doped graphene (NG) and TiO2 supported MnOx–CeO2 catalysts were prepared by a hydrothermal method. The catalysts with different molar ratios of Mn/Ce (6: 1, 10: 1, 15: 1) were investigated for the low-temperature selective catalytic reduction (SCR) of NO x with NH3. The synthesized catalysts were characterized by HRTEM, SEM, XRD, BET, XPS, and NH3-TPD technologies. The characterization results indicated that manganese and cerium oxide particles dispersed on the surface of the TiO2–NG support uniformly, and that manganese and cerium oxides existed in different valences on the surface of the TiO2–NG support. At Mn element loading of 8 wt%, MnO x –CeO2(10: 1)/TiO2–1%NG displayed superior activity and improved SO2 resistance. On the basis of the catalyst characterization, excellent catalytic performance and SO2 tolerance at low temperature were attributed to the high content of manganese with high oxidation valence, extensive oxidation of NO into NO2 by CeO2 and strong NO adsorption capacity, and electron transfer of N-doped graphene.