Influence of Mn/Ce ratio on the physicochemical properties and catalytic performance of graphene supported MnOx-CeO2 oxides for NH3-SCR at low temperature

Abstract A series of MnOx-CeO 2 /graphene catalysts prepared by a hydrothermal method with different molar ratios of Mn/Ce active components were loaded on graphene for low-temperature SCR of NOx with NH 3 . Experimental results indicated that these catalysts exhibited excellent low-temperature SCR activities and strong resistance against SO 2 . The characterization results indicated that manganese and cerium oxides dispersed on the surface of graphene uniformly, and that manganese oxide existed in different forms of crystallinities (MnO, Mn 3 O 4 , and MnO 2 ). The MnOx-CeO 2 (8:1)/GR displayed superior activity, high N 2 selectivity, and good resistance to H 2 O and SO 2 , which would be very attractive for the application in controlling NOx emission from flue gas. Its excellent catalytic performance and SO 2 tolerance at low temperature were attributed to the high content of manganese with high oxidation valence, increased chemisorbed oxygen on the surface, more active sites, and the strong interaction between MnOx-CeO 2 active sites and graphene support.