Effects of WO3 and SiO2 doping on CeO2-TiO2 catalysts for selective catalytic reduction of NO with ammonia.

Abstract

A series of CeO2–WO3/SiO2–TiO2 (CeWxTiSiy) catalysts with different loading amounts of WO3 were synthesized by wet co-impregnation of ammonium metatungstate and cerium nitrate on a SiO2–TiO2 support, and were employed for the selective catalytic reduction (SCR) of NO by NH3. The catalytic activity of the CeO2/SiO2–TiO2 (CeSiTi) catalyst was enhanced by the addition of WO3, and the W-containing catalysts showed higher hydrothermal stability especially between 550 and 600 °C. The introduction of WO3 to the CeSiTi catalyst could produce more chemisorbed oxygen species, reducible subsurface oxygen species, acid sites and ad-NOx species. Moreover, the modification of CeO2–WO3/TiO2 (CeWTi) by SiO2 could enhance the specific surface area, especially the aged specific surface area, thus improving the hydrothermal stability of the catalyst.