High resistance to na poisoning of the V 2 O 5 -Ce(So 4 ) 2 /TiO 2 catalyst for the no SCR reaction

Abstract

Poisoning by Na is one of the major issues for the commercial SCR catalyst. In this study, Ce(SO 4 ) 2 was added to the catalyst system of V 2 O 5 /TiO 2 to enhance its resistance to Na poisoning. The results show that the addition of Ce(SO 4 ) 2 increases the NO x conversion of the V 2 O 5 /TiO 2 catalyst at medium temperatures of 330°C–450°C. After being doped with sodium with a molar ratio of Na/V = 1/1, the V 2 O 5 -Ce(SO 4 ) 2 /TiO 2 catalyst still shows excellent DeNO x efficiency, about 40% higher than the commercial V 2 O 5 -WO 3 /TiO 2 catalyst. The fresh and Na-poisoned catalysts were characterized using XRD, SEM, NH 3 -TPD and H 2 -TPR. The results show that the Ce(SO 4 ) 2 addition remarkably strengthens the surface acidity and redox ability of the V 2 O 5 /TiO 2 catalyst. Furthermore, the TPD results show that the V 2 O 5 -Ce(SO 4 ) 2 /TiO 2 catalyst can maintain its surface acidity after being doped with Na, while the acidity of the V 2 O 5 -WO 3 /TiO 2 catalyst dramatically decreases. The redox ability of the catalyst can also be retained more effectively when Ce(SO 4 ) 2 is added to the catalyst system.