Formation of N₂O and SO₃ on mixed metal oxide V-W-Mo/Tio₂ catalyst during the selective reduction of NO by NH₃

Abstract

This research studied the formation of N₂O and SO₃ on mixed metal oxide V-W-Mo/TiO₂ catalyst during the selective reduction of NO by NH₃. This work use a catalyst of previous research (Piyanantarak, 2011) which the TiO₂ support was prepared by sol-gel method and V₂O5, WO₃, MoO₃ were loaded to TiO₂ support by the incipient wetness method. The catalysts have been already characterized by ICP-OES, nitrogen adsorption and NH₃-TPD. In this study the catalysts are additionally characterized by XRD and FT-IR techniques. The performances of V₂O5-WO₃-MoO₃/TiO₂ catalyst are measured in the reaction temperature range 120-450 °C. From the results it can be concluded that the SCR process probably occurred from Eley–Rideal mechanism and this mechanism determines the activity of SCR in the low temperature range. However in the high temperature range the amount of adsorbed NH₃ on surface catalysts determines how much NO conversion can be achieved. The formation of N₂O causes from the reaction between NO and adsorbed NH₃. The oxidation of NH₃ occurs via homogeneous between NH₃ and O₂ and via redox mechanism. The formation of SO₃ does not occur.