Enhancing the deNO performance of MnO /CeO2 ZrO2 nanorod catalyst for low temperature NH3 SCR by TiO2 modification
Abstract In the present work, we chose MnOx/CeO2 ZrO2 nanorod (i.e. Mn/CZ NR) as a benchmark catalyst, and used TiO2 as a modifier with the purpose of inhibiting the formation of N2O (by product) as well as further enhancing the catalytic activity and H2O SO2 tolerance of Mn/CZ NR catalyst. These samples were characterized by TEM, HRTEM, XRD, Raman, H2 TPR, XPS, NH3 TPD, and in situ DRIFTS. DeNOx performance and H2O SO2 tolerance of these samples were evaluated by low temperature NH3 SCR reaction. The obtained results show that the TiO2 modified catalyst (i.e. Mn Ti/CZ NR) exhibits higher catalytic activity than Mn/CZ NR catalyst due to larger amount of oxygen vacancy accompanied with more Ce3+ higher ratios of Mn4+ and surface adsorbed oxygen species, as well as the improvement of surface acidity. Furthermore, TiO2 modification effectively inhibits the non selective oxidation of NH3 to N2O through appropriately weakening the redox property of Mn/CZ NR catalyst, which is beneficial to the enhancement of N2 selectivity. Finally, Mn Ti/CZ NR catalyst exhibits excellent H2O SO2 tolerance, which indicates that it has the potential to be used for practical low temperature deNOx application.
Chemical Engineering Journal