Iron-doped Mn-Ce/TiO 2 catalyst for low temperature selective catalytic reduction of NO with NH 3

Abstract

Abstract The catalysts of iron-doped Mn-Ce/TiO 2 (Fe-Mn-Ce/TiO 2) prepared by sol-gel method were investigated for low temperature selective catalytic reduction (SCR) of NO with NH 3. It was found that the NO conversion over Fe-Mn-Ce/TiO 2 was obviously improved after iron doping compared with that over Mn-Ce/TiO 2. Fe-Mn-Ce/TiO 2 with the molar ratio of Fe/Ti = 0.1 exhibited the highest activity. The results showed that 96.8% NO conversion was obtained over Fe(0.1)-Mn-Ce/TiO 2 at 180°C at a space velocity of 50,000 hr −1. Fe-Mn-Ce/TiO 2 exhibited much higher resistance to H 2O and SO 2 than that of Mn-Ce/TiO 2. The properties of the catalysts were characterized using X-ray diffraction (XRD), N 2 adsorption, temperature programmed desorption (NH 3-TPD and NO x-TPD), and X-ray photoelectron spectroscopy (XPS) techniques. BET, NH 3-TPD and NO x-TPD results showed that the specific surface area and NH 3 and NO x adsorption capacity of the catalysts increased with iron doping. It was known from XPS analysis that iron valence state on the surface of the catalysts were in Fe 3+ state. The doping of iron enhanced the dispersion and oxidation state of Mn and Ce on the surface of the catalysts. The oxygen concentrations on the surface of the catalysts were found to increase after iron doping. Fe-Mn-Ce/TiO 2 represented a promising catalyst for low temperature SCR of NO with NH 3 in the presence of H 2O and SO 2.