Comprehensive understanding of the superior performance of Sm-modified Fe2O3 catalysts with regard to NO conversion and H2O/SO2 resistance in the NH3-SCR reaction

Sm-doped Fe2O3 catalysts, with a homogeneous distribution of Sm in Fe2O3 nanoparticles, were synthesized using a citric acid-assisted sol-gel method. Kinetic studies show that the reaction rate for NOx reduction using the optimal catalyst (0.06 mol% doping of Sm in Fe2O3) was nearly 11 times higher than that for pure Fe2O3, when calculated based on specific surface area. Furthermore, the Fe0.94Sm0.06Ox catalyst maintains > 83% NOx conversion for 168 h at a high space velocity in the presence of SO2 and H2O at 250 degrees C. A substantial amount of surface-adsorbed oxygen was generated on the surface of Fe0.94Sm0.06Ox, which promoted NO oxidation and the subsequent fast reaction between NOx and NH3. The adsorption and activation of NH3 was also enhanced by Sm doping. In addition, Sm doping facilitated the decomposition of NH4HSO4 on the surface of Fe0.94Sm0.06Ox, resulting in its high activity and stability in the presence of SO2 + H2O. (C) 2021, Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by Elsevier B.V. All rights reserved.

Automated summary

Sm-doped Fe2O3 catalysts show excellent catalytic performance and stability in NOx reduction, promoting fast reaction between NO and NH3.