Reasonably designed CuSbTiOx series catalysts with high NH3-SCR activity and obviously improved SO2 tolerance

Abstract

CuO/TiO₂ catalysts with varying Sb doping ratios were synthesized and applied in the NH₃-SCR process. The results of activity tests revealed that the addition of Sb effectively enhanced the performance of low-temperature SCR. Particularly, the CuSbTiO_x-0.2 catalyst exhibited the highest activity, achieving over 91% conversion at 250 °C, along with the highest N₂ selectivity and exceptional resistance to SO₂. Comprehensive characterization analyses demonstrated that CuSbTiO_x-0.2 possessed a significantly large specific surface area, the strongest surface acidity, and superior redox performance among the catalysts studied. In situ DRIFTS experiments provided further insights, indicating that Sb modification generated more active species, thereby enhancing the reactivity of ad-NH₃ and ad-NO_x species. The SCR reaction mechanism for CuSbTiO_x-0.2 predominantly followed the Langmuir–Hinshelwood (L–H) and Eley–Rideal (E–R) mechanisms. These findings have the potential to advance the development of novel and effective non-vanadium SCR catalysts.