The promotion effect of Pr doping on the catalytic performance of MnCeOx catalysts for low-temperature NH3-SCR.

[Display omitted] • Pr-modified MnCeO x catalysts exhibited excellent SCR performance and SO 2 tolerance. • The SCR reaction pathways based on both L-H and E-R mechanisms were investigated. • The ad-NH 3 species on MnCePrO x -0.3 showed superior reactivity. • Abundant of O ads and Mn4+ on MnCePrO x -0.3 catalysts promoted the "fast SCR". Using a one-step impregnation method, a series of Pr-modified MnCeO x catalysts with different Pr molar ratios were created to manufacture an efficient and effective catalyst for low-temperature NH 3 -SCR. It was demonstrated that the Pr modification could extensively boost the MnCeO x catalysts' de-NO x activity and SO 2 resistance and led to the formation of a unique broom-like morphology, especially when the molar ratio of Pr/Mn = 0.3, the MnCePrO x -0.3 exhibited above 90 % NO conversion at 250 °C with the existence of 100 ppm SO 2. According to the characterization results, the enhancement of Pr doping for MnCeO x catalysts was mainly manifested by the expanded specific surface area, the improved dispersion of active components, the enhanced surface acidity and redox ability, and the generated more chemisorbed oxygen (O ads) species. All these characteristics allowed the NH 3 -SCR reaction over MnCePrO x -0.3 catalysts to proceed through the both Eley-Rideal (E-R) and Langmuir-hinshelwood (L-H) mechanism. [ABSTRACT FROM AUTHOR]