MnO dispersion regulated P-Mn interactions in P-doped MnO /TiO2 catalyst for efficient NH3-SCR denitration

Modification with strong acidic species serves as an effective strategy to broaden the active temperature window of MnO x based catalysts for ammonia selective catalytic reduction (NH 3 -SCR) of NO x . However, strong acidic species always decrease the redox properties of MnO x , which hinders the quest for better performance of MnO x based NH 3 -SCR catalysts. Herein, the dispersion of MnO x on P modified MnO x /TiO 2 (labeled as Mn(X)/TiP (X = O, A, N, represents the Mn precursors of manganese dioxide, manganese acetate and manganese nitrate, respectively)) catalysts were regulated via changing manganese precursors to investigate its effects on P-Mn interactions and catalytic performance. It is found that the low-temperature NH 3 -SCR performance follows the order Mn(A)/TiP > Mn(O)/TiP > Mn(N)/TiP, which is consistent with the degree of MnO x dispersion. The increase of MnO x dispersion can contribute to the formation of a large amount of isolated MnO x nanoparticles, which reduces the passivation of P on other active Mn sites due to the formation of P-Mn interactions and promotes the establishment of an efficient redox cycle between Mn and Ti (Ti 4+ + Mn 2+/3+ ↔ Ti 3+ + Mn 3+/4+ ), thereby promoting the NH 3 -SCR denitration reaction via enhancing the activation of NH 3 and NO x . This work sheds an insight into the effect of MnO x dispersion on regulating the NH 3 -SCR performance of P-modified MnO x /TiO 2 catalysts and provides an efficient strategy to solve the imbalance between acidity and redox property during the design and developments of efficient NH 3 -SCR catalysts.