The Effect of Fe2O3 Modification on the CeO2-MnO2/TiO2 Catalyst for Selective Catalytic Reduction of NO with NH3.

High denitration efficiency and strong adaptability to flue gas temperature fluctuations are the core properties of the NH3-SCR catalyst. In this study, Fe2O3 modification is used as a means to explore the mechanism of adding Fe2O3 to broaden the temperature range of the 6CeO2-40MnO2/TiO2 catalyst during the preparation process. The results show that the 6Fe2O3-6CeO2-40MnO2/TiO2 catalyst exhibits excellent denitration performance, with a denitration efficiency higher than 90%. The temperature range is from 129 to 390 °C. N2 selectivity and resistance to SO2 and H2O are good, and the denitration performance is significantly improved. When the Fe2O3 content is 6%, it promotes lattice shrinkage of TiO2, improves its dispersion, refines the grain size, and increases the specific surface area of the catalyst. At the same time, Fe2O3 enhances the chemical adsorption of oxygen on the catalyst surface and increases the proportion of low-cost metal ions, thereby promoting electron transfer between active elements, generating more surface reactive oxygen species, increasing the oxygen vacancy content and adsorption sites for NOx and NH3, and significantly improving the redox performance of the catalyst. This effect is particularly conducive to the formation of strong acid sites on the catalyst surface. The NH3-SCR reaction on the surface of the 6Fe2O3-6CeO2-40MnO2/TiO2 catalyst follows both the L-H and E-R mechanisms, with the L-H mechanism being dominant.