Fe-Doped Mn<sub>3</sub>O<sub>4</sub> Spinel Nanoparticles with Highly Exposed Fe<sub>oct</sub>–O–Mn<sub>tet</sub> Sites for Efficient Selective Catalytic Reduction (SCR) of NO with Ammonia at Low Temperatures
Zhi Liu, Guangxun Sun, Chong Chen, Kaian Sun, Lingyou Zeng, Lingzhi Yang, Yanju Chen, Wenhong Wang, Bin Liu, Yukun Lu, Yuan Pan, Yunqi Liu, Chenguang Liu
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.