CeO2-WO3 catalysts for the selective catalytic reduction of NOx with NH3: effect of the amount of WO3

CeO2-WO3 (CW) catalysts were prepared by situ self-assembly method for the selective catalytic reduction (SCR) of NOx with NH3. With the increasing content of WO3, the interaction between WO3 and CeO2 improved, resulting in the formation of more acid sites, CeO2-WO3 solid solution and excellent redox ability, which could enhance the catalytic activity. Furthermore, an excess of WO3 over CW catalysts could decrease the SCR activity due to the attenuation of interaction. Hence, CW-20 (WO3 was 20 wt% over CeO2-WO3) possessed the widest active temperature window and nearly 100% NOx conversion was obtained at 225–400 °C, which relied on the contents of WO3.