Investigation of the effect of Cu addition on the SO2-resistance of a CeTi oxide catalyst for selective catalytic reduction of NO with NH3

Abstract A series of characterizations including TEM–EDS, XRD, FTIR, SO 2  + O 2 TPD, XPS, H 2 -TPR and NH 3 -TPD has been carried out to explore the mechanism of the promoting effect of Cu addition on the SO 2 -resistance of the Ce Ti oxide catalyst. SO 2 had been found to strongly interact with surface cerium oxygen and result in the reduction of Ce 4+ to Ce 3+ on the Ce Ti oxide catalyst. The Cu atoms in the Ce Cu Ti oxide catalyst will preferentially interact with SO 2 and preserve the adjacent Ce 4+ . The redox ability of the Ce Ti catalyst was found to significantly decrease due to the sulfation by SO 2 . Due to the formation of CuSO 4 and the preserved Ce 4+ , the reducibility of the Ce Cu Ti catalyst has not significantly decreased like the Ce Ti catalyst but slightly decreased to an adequate level for SCR reaction after sulfation. The surface acidities of Ce Ti and Ce Cu Ti were both enhanced by sulfation. The preservation of the redox ability and the increase of surface acidity after sulfation had caused Ce Cu Ti to be a high SO 2 -resistance catalyst for SCR reaction. A graphical description of the effect of the Cu addition on the SO 2 -resistance of a Ce Ti oxide catalyst has also been proposed.