Fe-Doped Mn₃O₄ Spinel Nanoparticles with Highly Exposed Fe_oct–O–Mn_tet Sites for Efficient Selective Catalytic Reduction (SCR) of NO with Ammonia at Low Temperatures

Abstract

The development of highly active catalysts for ammonia selective catalytic reduction (NH3-SCR) of NO at low temperatures and the exploration of efficient catalytic active sites are desirable but still challenging. Herein, a series of FexMn3–xO4 nanoparticles (NPs) were synthesized, derived from Mn–Fe bimetallic MOFs. The Fe0.35Mn2.65O4 NPs exhibit a NO conversion up to 90% at 180 °C in an ultrahigh GHSV of 400 000 h–1. An efficient Feoct–O–Mntet site is revealed, and the formation energy of oxygen vacancy on the Feoct–O–Mntet site is the lowest, which is the rate-determining step of NO oxidation. The high NO oxidation activity can trigger the "fast SCR" reaction, thus leading to the boosted NH3-SCR performance. This work provides not only an approach to construct NH3-SCR catalysts with high intrinsic activity but also the potential to resolve industrial challenges related to NO catalytic reduction.