Synthesis and Characterization of Mn–Ce–VO x /TiO 2 Nanocomposite for SCR of NO x at Low Temperatures: Role of Mn, Ce and V Oxide

Mn–Ce–VO x /TiO 2 (MnCeVTi), Mn–CeO x /TiO 2 (MnCeTi) and Mn–VO x /TiO 2 (MnVTi) nanocomposites as SCR DeNO x catalysts were synthesized by a modified sol–gel method. All catalysts shows high NO x conversion of over 90% at low temperature between 125 and 200 °C with GHSV of 30,000 h −1 . MnCeVTi catalyst demonstrates the highest NO x conversion and produces the least byproduct N 2 O at 110–310 °C. The co-presence of Ce, V and Mn inhibits the growth of rutile, decreases crystallinity of anatase TiO 2 and manganese oxides, reduces grain size, increases BET specific surface area and pore volume. There are most chemisorbed oxygen, appropriate Mn 3+ /Mn 4+ and the synergistic effect of Ce and V on MnCeVTi sample. The acid sites on MnCeVTi are most below 280 °C and in widest temperature range. Lewis acid sites play a leading role in SCR reaction on MnCeVTi catalyst. These helps to optimize the SCR catalytic performance of MnCeVTi, on which E-R and L–H mechanism may coexist in the reaction.