Iron based monolithic catalysts supported on Al2O3, SiO2, and TiO2: A comparison for NO reduction with propane

Abstract

The selective catalytic reduction of NO with propane has been investigated with iron based monolithic catalysts supported on alumina, silica, and titania. The catalysts were characterized by N2-physisorption, XRD, SEM, XPS, H2-TPR, Py-FTIR and in situ DRIFTS technologies. The different supports had a significant influence on specific surface area, surface morphology, lattice oxygen, redox properties and the acid sites, which resulted in differences in the catalytic activity of NO reduction. The C3H8-SCR performance decreased in the order as Fe/Al2O3/CM > Fe/SiO2/CM > Fe/TiO2/CM. Fe/Al2O3/CM showed the highest activity with a nitrogen oxide conversion of 100% in the presence of oxygen at 500 °C,which is mainly attributed to the good redox properties and the abundant Lewis acid sites. Based on in situ DRIFT studies, the increase of Lewis acid sites will enhance the formation of NO2/NO3− species and acetate/formate species, then promote the catalytic activity.