Investigation of the surface acidity and redox on the CeO₂-WO₃ catalyst for selective catalytic reduction with NH₃

CeO₂-WO₃ catalysts were successfully prepared by in-situ synthesis and used in the denitrification reaction. The best activity of CW-550 catalyst was achieved at a roasting temperature of 550 ℃, and the denitrification activity of CW-550 reached over 90% at 200 ℃. The superior catalytic performance of CW-550 catalyst can be attributed to the large specific surface area, more Ce³⁺ species, abundant surface acidity and superior redox performance. The increased Ce³⁺ facilitates the formation of oxygen vacancies and promotes redox performance. The introduction of WO₃, into CeO₂ can enhance the amounts of Brönsted acid, which contributes to the improvement of the adsorption and activation of ammonia, resulting in the excellent catalytic performance. The NH₃-adsorbed species can react with gaseous NO. However, both of NH₃-adsorbed and NO-adsorbed sepcies cannot participate in the SCR reaction effectively. Therefore, the SCR reaction of CW catalysts mainly follows the Eley-Rideal mechanism.