Ceria-modified WO3-TiO2-SiO2 monolithic catalyst for high-temperature NH3-SCR

WO3/TiO2-SiO2 (WTiSi) and CeO2-WO3/TiO2-SiO2 (CeWTiSi) monolithic catalysts were prepared by a solid phase synthesis. Ceria-modified WTiSi catalysts (CeWTiSi) show higher NH3-SCR activities in the 450-550 degrees C range and higher hydrothermal stability at 550 degrees C. The catalysts were characterized by Raman spectroscopy, H-2 temperature-programmed reduction (H-2-TPR) and temperature-programmed desorption of ammonia (NH3-TPD). The thermal stability and tolerance towards H2O and SO2 were investigated for the deactivation of WTiSi upon aging. Possible phase transformation of anatase TiO2 to rutile, crystallization of polytungstate, and the role of ceria were investigated.