Promotion effect of Ce and Ta co-doping on the NH₃-SCR performance over V₂O₅/TiO₂ catalyst

NH₃-SCR (SCR: Selective catalytic reduction) is an effective technology for the de-NO_x process from both mobile and stationary pollution sources, and the most commonly used catalysts are the vanadia-based catalysts. An innovative V₂O₅-CeO₂/TaTiO_x catalyst for NO_x removal was prepared in this study. The influences of Ce and Ta in the V₂O₅-CeO₂/TaTiO_x catalyst on the SCR performance and physicochemical properties were investigated. The V₂O₅-CeO₂/TaTiO_x catalyst not only exhibited excellent SCR activity in a wide temperature window, but also presented strong resistance to H₂O and SO₂ at 275 ℃. A series of characterization methods was used to study the catalysts, including H₂-temperature programmed reduction, X-ray photoelectron spectroscopy, NH₃-temperature programmed desorption, etc. It was discovered that a synergistic effect existed between Ce and Ta species. The introduction of Ce and Ta enlarged the specific surface area, increased the amount of acid sites and the ratio of Ce³⁺, (V³⁺+V⁴⁺) and O_α, and strengthened the redox capability which were related to synergistic effect between Ce and Ta species, significantly improving the NH₃-SCR activity.