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

Environ Sci Pollut Res Int. 2024 Dec 22. doi: 10.1007/s11356-024-35751-z. Online ahead of print.

Abstract

The enhancement effect of Ce modification on V2O5-WO3/TiO2 catalysts at low temperatures was investigated for the selective catalytic reduction (SCR) of NOx with NH3 (NH3-SCR). By adding 9% CeO2 to 0.5%V2O5-3%WO3/TiO2 catalyst, the low-temperature denitrification performance of Ce9V0.5W3Ti 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% V2O5-3% WO3/TiO2. The catalysts were characterized by XPS, H2-TPR, NH3, and NO-TPD. The results indicated that the Ce additive could enhance the adsorption of NOx on Ce9V0.5W3Ti catalyst due to the synergetic interaction among the Ce and V, W species. The interaction between V and Ce also promoted the formation of V5+ and Ce3+ 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 NH3-SCR reaction process, resulting in a significant enhancement of the catalyst's low-temperature catalytic activity.

Keywords: Ce modification; Low temperature activity; NH3-SCR; Synergistic effect; V2O5-WO3/TiO2 catalyst.