Catalytic Performance and Characterization of Ce-Modified Fe Catalysts Supported on Al2O3 for SCR-C3H8

Abstract

In order to further improve the resistance of the catalysts to H2O and SO2 during the selective catalytic reduction of NO with C3H8 (SCR-C3H8), Ce was used to modify the Fe-based catalysts. Sol–gel and impregnation methods were adopted to prepare the monolithic cordierite Ce–Fe/Al2O3 catalysts and the SCR-C3H8 testes were carried out in a flow reactor, electrically heated up to 600 °C, and with simulated a flue gas rate of 1.5 L/min. The physical chemical properties of the catalysts were characterized by XRD, N2 adsorption–desorption, SEM, H2-TPR and FT-IR spectra of adsorbed pyridine, etc. Results show that the introduction of Cerium notably enhances the resistance of the Fe/Al2O3/Cordierite catalysts to SO2. 3.5Ce–Fe/Al2O3/Cordierite has the highest C3H8-SCR activity, e.g., the NO reductions are 96.5% and 93% at 600 °C when there was no and 0.02% SO2 in the flue gas, respectively. While the NO reduction by Fe/Al2O3/Cordierite decreased from 88 to 80% in the presence of 0.02% SO2. The addition of Cerium to iron oxide leads to an increase in the Lewis acid sites and the redox property of the catalysts. However, an overload of cerium will reduce the crystallinity of iron oxide nanorods and inhibit the formation of the NO2/NO3− species in the C3H8-SCR reaction, resulting in a decrease in the NO reduction.