(521ep) Promoting the Enhancement of Low-Temperature Activity and N2 Selectivity for NH3-SCR Catalysts Via Changing the Interaction between Fe-Mn Sites

Manganese modified Fe₂O₃ catalyst is an effective way to replace the traditional commercial NH₃-SCR catalyst to achieve low temperature and high selectivity removal of NO_x to N₂ from gas emission of fixed sources. In order to clarify the influence mechanism of different interaction modes between Mn and Fe on the NO_x conversion and N₂ selectivity of catalysts at low temperature, Mn doped Fe₂O₃ and MnO₂ loaded Fe₂O₃ are prepared by co-precipitation method and impregnation method respectively. It is demonstrated that the doped Mn cations can provide more Lewis acid sites and more abundant Mn⁴⁺ species, which lead to the improvement of NO_x conversion at low temperature. Meanwhile, doped Mn cations activate the oxidation ability of surrounding Fe atoms through the strong electron transfer between Mn and Fe, making Fe become the main reaction site of NH₃ oxidation into NH₂ species, and inhibit its excessive oxidation to NH species. This mechanism provides theoretical support for exploring the interaction between binary metal oxides and improving the activity and N₂ selectivity of NH₃-SCR catalysts at low temperature.