The promotion effect of ceria on high vanadia loading NH3-SCR catalysts

Abstract A high vanadia loading (5 wt%) catalyst was modified by ceria to improve the NH 3 -SCR performance. CeVO 4 was generated after the addition of ceria to 5 wt% V 2 O 5 /TiO 2 , result not seen in the case of low-loading vanadia samples. CeVO 4 presented stable Bronsted acid sites for NH 3 adsorption and moderate redox sites for NH 3 activation rather than polymeric VO x for the V-based catalyst. These properties effectively suppressed formation of N 2 O and NO (side reactions). Therefore, ceria preserved the low-temperature activity of V 2 O 5 /TiO 2 and improved its high-temperature N 2 selectivity. Furthermore, ceria promoted the resistance of V 2 O 5 /TiO 2 to SO 2 and H 2 O poisoning.