Experimental study on selective catalytic reduction of NO by C₃H₆ over Fe/Ti-PILC catalysts

Ti-pillared interlayer clay (PILC)-based catalysts ion exchanged with Fe were prepared and used for selective catalytic reduction of NO_x using propylene as the reducing agent under oxygen-rich conditions. The relationship between structure and properties of the catalysts was studied using N₂-adsorption/desorption, XRD, UV-vis, H₂-TPR, and Py-FTIR. The results show that the prepared 19Fe/Ti-PILC catalyst can achieve complete removal of NO at 400 ℃, and N₂ selectivity can reach over 90% and has better resistance to water vapor and SO₂. N₂-isothermal adsorption/desorption and XRD results show that structure of montmorillonite is opened, cross-linked pillars are effective, and a large specific surface area and pore volume are formed. UV-vis results show that the denitrification activity of the catalyst is related to content of oligomeric Fe_xO_y. Py-FTIR results show that both Lewis acid and Brønsted acid are presented on the catalyst surface. Fe³⁺ loading into the pillared clay can significantly increase the Lewis acid content. Lewis acid is one of the influencing factors on the denitrification activity of the catalyst. H₂-TPR indicates that the catalyst has a strong reduction ability at about 400 ℃, and the reduction ability of the catalyst is mainly represented by the reduction of Fe³⁺→Fe²⁺.