Novel V2O5-CeO2-TiO2-SO42- nanostructured aerogel catalyst for the low temperature selective catalytic reduction of NO by NH3 in excess O-2

New ceria and sulfate co-modified V2O5-TiO2 aerogel catalysts were developed, using the one-step sol gel method associated with the supercritical drying process, for Diesel DeNO(x) technology. N-2 adsorption-desorption, XRD, H-2-TPR, NH3-TPD, Raman and DRUV-Vis spectroscopy were employed to probe the physico-chemical properties of TiO2, V2O5-TiO2, V2O5-CeO2-TiO2 and V2O5-CeO2-TiO2-SO42- aerogel materials. XPS was used to obtain further information about the oxidation states of the active sites on the surface of the novel V2O5-CeO2-TiO2-SO42- aerogel catalyst. The characterization results showed the successful synthesis of a new generation of well nanostructured aerogel catalysts with high surface area, large porosity and good thermal stability. V, Ce and SO42- actives species were found highly dispersed on TiO2 surface and their presence strongly influenced the surface acidity and the redox properties of the aerogel catalysts. Sulfate anions created strong acid sites and most probably contributed to the stabilization of V and Ce surface species at their 4 + and 3 + oxidation state, respectively. In the SCR-NO by NH3 under oxygen rich conditions, V2O5-TiO2 aerogel catalyst exhibited low NO conversions in 150-500 degrees C temperature range. The addition of cerium significantly increased the NO conversion at low temperature (220-400 degrees C). However, the simultaneous incorporation of cerium and sulfate has led to a novel V2O5-CeO2-TiO2-SO42- nanostructured aerogel catalyst with superior catalytic performances, at high temperature (450-500 degrees C), with respect to V2O5-WO3/TiO2 commercial one (EUROCAT).