The study of NH3-SCR mechanism on γFe2O3 supported LaMnO3 catalyst based on DFT

Abstract

Fe₂O₃ supported LaMnO₃ is an effective selective catalytic reduction (SCR) denitrification catalyst, but its reaction mechanism has not been reported yet. This article is based on the density functional theory (DFT) method to study the denitrification reaction mechanism of LaMnO₃/Fe₂O₃ catalyst, in order to guide the development and application of denitrification catalysts. The conclusion is as follows: NH₃, NO, and O₂ molecules can form stable adsorption on the surface of La MnO₃/γFe₂O₃ catalysts, and NH₃ molecules are more likely to be adsorbed on Mn ions. Under the oxidation of lattice oxygen, NH₃ will gradually dehydrogenate to form NH₂, and then will react with NO in the air to form the transitional intermediate NH₂NO, to produce N₂ and H₂O. The mechanisms are same on Mn and Fe sites. The dehydrogenate of NH₃ to form NH₂ is rate determining step. Compared with pure γFe₂O₃, the energy barrier decreases to promote the SCR process.