SCR performance and mechanism study with multiple poisoning gases on CeOx promoted V2O5-WO3/TiO2 monolithic honeycomb catalyst of NOx removal
Mingyu Guo, Jing Gao, Ke Niu, Yidan Huang, Meng Xiao, Yingjie Zhao, Shaoping Cui, Wei Ye, Boqun Liu
Abstract
The V 2 O 5 -WO 3 -TiO 2 catalysts are commonly used in the selective catalytic reduction of ammonia for NO x removal. Coated VWTi and Ce promoted VWTi monolithic catalysts were prepared to compare the SCR performance and anti-poisoning properties. The VWTi catalyst demonstrated more than 90 % NO conversion in the range of 300–500 ℃, which decreased to about 50 % NO conversion after multiple gases poisoning. However, the CeVWTi catalyst demonstrated more than 90 % NO removal efficiency in the range of 250–500 ℃, remaining about 60 % after multiple gases poisoning. In contrast to the fresh catalysts, the presence of SO 2 /H 2 O/C 3 H 8 caused the catalysts redox properties decreased and the inert acid sites formated on the VWTi surface. However, CeO 2 provided surface adsorbed oxygen and mitigated these negative effects to some extent. The in situ DRIFTs results indicated that SO 2 inhibited the reaction and prevented the NH 3 and NO adsorption on the surface of the 7CeVWTi catalyst. The decreased NO conversion in the presence of H 2 O and C 3 H 8 was due to the competition adsorption with NH 3 species. Overall, the doping of CeO 2 improved the catalytic activity and poisoning resistance ability of the VWTi catalyst.