Selective Catalytic Reduction of NO_x with NH₃ Over Fe Modified MOF-Derived MnO_x Catalyst

A Fe modified MOF-derived MnO_x catalyst has been synthesized and studied for the selective catalytic reduction of NO_x with NH₃ (NH₃-SCR). Compared with pure MnO_x, Fe-modified MnO_x showed a broader activity temperature window, enhanced N₂ selectivity, and improved sulfur tolerance. On one hand, the incorporation of Fe into MnO_x increased acidity, thereby facilitating the adsorption of NH₃ as well as its activation, which plays a crucial role for the reduction of NO_x. On the other hand, the presence of Fe resulted in decreased Mn⁴⁺, which contributes to improved N₂ selectivity. Over Fe modified MnO_x catalyst, the coordinated NH₃, NH₄⁺, bridging nitrate and bidentate nitrate are reactive, and participate in the NH₃-SCR reaction following both “Eley–Rideal(E-R)” and “Langmuir–Hinshelwood(L–H)” mechanism. The present research provides an idea for broadening the activity temperature window and enhancing the sulfur tolerance of MnO_x catalyst for the reduction of NO_x, making it more suitable for practical application.