Spatially Confined Tuning the Interfacial Synergistic Catalysis in Mesochannels toward Selective Catalytic Reduction

Low-temperature selective catalytic reduction of nitrogen oxides (NO _x) with NH₃ (NH₃-SCR) has been identified as a promising strategy to mitigate the pollution of NO _x. The fine control of synergistic effect and the suppression of aggregation of the active component, however, are still the challenge because of the weak interaction between the active component and matrix. In this work, a series of Ce-promoted Mn-based heterogeneous catalysts supported on mesoporous silica (SBA-15) with different Mn contents were prepared by two separated impregnation processes. Low-temperature NH₃-SCR activity demonstrates that the Mn content in the catalyst has a great influence on the activity of the NH₃-SCR reaction. The 20% MnO _x-CeO _x/SBA-15 catalyst exhibited the best catalytic performance in a broad temperature window. Moreover, it exhibits enhanced resistance to SO₂ and H₂O and long-term durability during 72 h reaction. The highly dispersive active phase, the formation of solid solution, the high ratio of Ce³⁺, and the spatial confinement effect largely contribute to the outstanding activity and durability of the 20% MnO _x-CeO _x/SBA-15 catalyst. Finally, a monolithic catalyst fabricated by the 20% MnO _x-CeO _x/SBA-15 catalyst powder and cordierite substrate show promising industrial application.