Iron-doped Mn-Ce/TiO2 catalyst for low temperature selective catalyticreduction of NO with NH3

The catalysts of iron-doped Mn-Ce/TiO2 (Fe-Mn-Ce/TiO2) prepared by sol-gel method were investigated for low temperatureselective catalytic reduction (SCR) of NO with NH3. It was found that the NO conversion over Fe-Mn-Ce/TiO2 was obviously improvedafter iron doping compared with that over Mn-Ce/TiO2. Fe-Mn-Ce/TiO2 with the molar ratio of Fe/Ti = 0.1 exhibited the highestactivity. The results showed that 96.8% NO conversion was obtained over Fe(0.1)-Mn-Ce/TiO2 at 180°C at a space velocity of 50,000hr??1. Fe-Mn-Ce/TiO2 exhibited much higher resistance to H2O and SO2 than that of Mn-Ce/TiO2. The properties of the catalysts werecharacterized using X-ray di raction (XRD), N2 adsorption, temperature programmed desorption (NH3-TPD and NOx-TPD), and Xrayphotoelectron spectroscopy (XPS) techniques. BET, NH3-TPD and NOx-TPD results showed that the specific surface area and NH3and NOx adsorption capacity of the catalysts increased with iron doping. It was known from XPS analysis that iron valence state on thesurface of the catalysts were in Fe3+ state. The doping of iron enhanced the dispersion and oxidation state of Mn and Ce on the surfaceof the catalysts. The oxygen concentrations on the surface of the catalysts were found to increase after iron doping. Fe-Mn-Ce/TiO2represented a promising catalyst for low temperature SCR of NO with NH3 in the presence of H2O and SO2.