Unraveling the Poisoning Resistance Mechanism of an In Situ Fabricated SiO2/CoMnFe Layered Double Oxide Catalyst to NH3-SCR

A SiO2/CoMnFeOx composite catalyst was rationally fabricated via interfacial engineering and structural regulation. The optimized SiO2(0.5)/Co0.5Mn1.5Fe1Ox delivered remarkable SCR performance, achieving over 90% NOx conversion and 80% N2 selectivity within a temperature window of 150-250 °C. During a 30 h long-term stability test at 200 °C, the optimized catalyst exhibited greatly improved tolerance to poisoning. The improved N2 selectivity was verified to originate from the inhibited generation of N2O by‑products. The exceptional NH3-SCR activity is primarily attributed to the abundant surface-adsorbed oxygen species and exposed active sites of the catalyst, as well as the synergistically balanced surface acidity and redox properties. Furthermore, the main catalytic reaction and the intrinsic antipoisoning mechanism were elucidated through DFT analysis and in situ DRIFTS technology. This work establishes an innovative and reliable strategy for developing efficient NH3-SCR technology.