Boosting the H2O resistance and NH3-SCR activity over sulfated FeCe0.5 SmaTi4Ox-S catalysts by Sm modification

In this work, a series of Sm modified sulfated FeCe0.5Ti4Ox-S catalysts were successfully prepared by a concise one-step co-precipitation method for application in flue gases denitrifications (de-NOx) generated from high sulfur content coal-fired power plants. The catalysts were carried out by XRD, Raman, N2 adsorption and desorption, TEM, EDS spectroscopy, NH3-TPD, H2-TPR, XPS, and in-situ DRIFTS characterization. Among these catalysts, FeCe0.5Sm0.3Ti4Ox-S showed the best catalytic activity, maintaining 100% NO conversion in 260–450 °C, high N2 selectivity and good resistance to water and SO2 poisoning. The results demonstrated that the addition of appropriate amount of Sm promoted the interaction between Sm, Ce, Fe and Ti, which increased the oxidation capacity and L-acid sites on the catalyst surface, improving the catalytic activity. Additionally, the increase of L acid sites also contributed to the improvement of water resistance of the catalyst. In-situ DRIFTS studies also indicated that the Sm addition promoted NH3 adsorption in the presence of water due to the reaction of special surface sulfates with H2O to form additional B acid sites, which may be the reason for the negligible effect of water on the catalytic activity. Based on various characterizations, the NH3-SCR de-NOx processes are proposed over FeCe0.5Sm0.3Ti4Ox-S in presence of H2O.