Promotional effect and mechanism of Ce-modified V2O5-WO3/TiO2 catalyst in low-temperature NH3-SCR

The enhancement effect of Ce modification on V 2 O 5 -WO 3 /TiO 2 catalysts at low temperatures was investigated for the selective catalytic reduction (SCR) of NO x with NH 3 (NH 3 -SCR). By adding 9% CeO 2 to 0.5%V 2 O 5 -3%WO 3 /TiO 2 catalyst, the low-temperature denitrification performance of Ce 9 V 0.5 W 3 Ti catalyst after Ce modification was significantly improved, achieving a NO conversion above 90% within a broad temperature range of 200–350℃, with catalytic activity comparable to that of 3% V 2 O 5 -3% WO 3 /TiO 2 . The catalysts were characterized by XPS, H 2 -TPR, NH 3 , and NO-TPD. The results indicated that the Ce additive could enhance the adsorption of NO x on Ce 9 V 0.5 W 3 Ti catalyst due to the synergetic interaction among the Ce and V, W species. The interaction between V and Ce also promoted the formation of V 5+ and Ce 3+ on the surface of the catalyst, which was conducive to enhancing the adsorption and oxidation capacity of the catalyst for NO. Additionally, the introduction of Ce led to a substantial deposition of nitrate species on the surface of the catalyst, especially the increase of nitrite species, which was beneficial to the NH 3 -SCR reaction process, resulting in a significant enhancement of the catalyst’s low-temperature catalytic activity.