SCR performance and mechanism study with multiple poisoning gases on CeOx promoted V2O5-WO3/TiO2 monolithic honeycomb catalyst of NOx removal

• Multiple poisoning gases of monolithic SCR catalysts was studied, combining fundamental research and practical application. • CeO x enhanced the SCR performance in the low temperature region and in the presence of multiple poisoning gases. • Reaction with C 3 H 8 promoted the formation of Ce 3+ and active oxygen on the 7CeVWTi surface. • SO 2 affected NH 3 adsorption and slowed down the reaction rate, leading to the decreased SCR performance lower than 275 ℃. • The C 3 H 8 and H 2 O deactivation was due to the competed adsorption with NH 3 on the V=O and W=O sites of 7CeVWTi catalysts. 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.