Promotional Effect of Ce-doped V2O5-WO3/TiO2 with Low Vanadium Loadings for Selective Catalytic Reduction of NOx by NH3

The effect of the additive Ce on V2O5-WO3/TiO2 with low vanadium loadings for the selective catalytic reduction (SCR) of NOx with NH3 was investigated. The catalytic activity of 0.1% V2O5-6% WO3/TiO2 (V0.1W6T1) was greatly enhanced by the addition of 10 wt % of Ce in the broad temperature range of 200-500 degrees C. The catalysts were characterized by BET, XRD, XPS, TPD, H-2-TPR, and DRIFTS. The results indicated that the active components of V and W were well-dispersed, while it small cluster of cubic CeO2 appeared over the V0.1W6Ce10Ti catalyst The Cc additive could enhance the NOx adsorption and then accelerate the SCR reaction due to the synergetic interaction among the Ce and V,W species Ce mainly existed in the form of Ce3+ oxide in V0.1W6Ce10Ti catalysts, which was beneficial for the oxidation of NO to NO, Moreover, the DRIFTS results showed that the Ce additive on V0.1W6Ti could provide stronger and more active Bronsted acid sites, which were beneficial for the SCR reaction. The Ce additive also enhanced (lie reaction rate because the ad-NH4+ disappeared quickly in the presence of NO and O-2. NO2, nitrate, and nitrite species formed on the Ce-doped VWTi catalyst because NO was easily oxidized due to the addition of Ce on V0.1W6Ti.