Enhanced Activity of Nb-modified CeO2/TiO2 Catalyst for the Selective Catalytic Reduction of NO with NH3

A series of CeO2-Nb2O5/TiO2 catalysts were prepared by an impregnation method and investigated for the selective catalytic reaction (SCR) of NO with NH3. The 15 wt.% CeO2–10 wt.% Nb2O5/TiO2 catalyst (CeNbTi) exhibited the highest activity and resistance to a high gas hourly space velocity and K2O. In the presence of H2O and SO2, it also showed better activity than the CeTi catalyst. The addition of Nb could improve the dispersion of CeO2 and increase the amount of Ce3+ and chemisorbed oxygen species on the catalyst surface, which enhances the catalytic activity of CeTi. The superior SCR activity of CeNbTi might also be attributed to its high redox ability, the enhanced adsorption capacity of NH3 species and the synergistic action between Ce, Nb and Ti species.