To Nano Zro <sub> 2 </ Sub> The Preparation And Properties Of Low-temperature Scr Catalyst Carrier

Nitride oxide (NOx) is one of the important pollutants in the atmosphere. Selective Catalytic Reduction (SCR) has been generally recognized as the best removal technology of NOx emitted from the stationary sources. But the commercial SCR catalysts, such as V2O5/TiO2 or V2O5-(WO3)/TiO2, require a high reaction temperature (over 350℃). We need to preheate the flue gas, which will result in. waste of energy. In order to reduce the cost, developing the catalysts with highly activity for low-temperature SCR of NOx become a research focus. In recent research of catalysts, Mn-based catalysts have good low-temperature activity. So, a new style Mn-based catalyst which has excellent low-temperature activity was prepared using nano-Zirconia as the catalyst vector.First of all, the tetragonal ZrO2 powder with large surface area and stable crystal structure was prepared by co-precipitation, as the catalyst vector. Secondly, the MnOx-CeO2/ZrO2 catalyst was prepared by impregnation method. The influence of catalyst properties on the NOx removal efficiency were examined, such as chemical composition, additives types, reaction temperature. Then the best ratio of catalyst components was filtered out. The results showed that when MnOx loading was 10wt%, Mn/Ce molar ratio was 2, adding 8wt% Fe to the catalyst, in the absence of SO2 and H2O, the NOX removal efficiency reached 85.23% at 120℃. The catalyst activity was greatly improved because of addition of Fe. In addition, the effect of SO2 and H2O on catalyst activity was discussed. When SO2 and H2O both presence, the concentration of SO2 would seriously affect the life of the catalyst. When SO2 concentration was 500×l0-6, the NOx removal efficiency decreased from nearly 90% to 53.84% for only 2 hours. The deactivation catalyst was activation at 400℃for regeneration, however, the catalyst activity after regeneration can not be all restored.Properties of the catalysts were characterized by X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Brunauer Emmett Teller (BET) and other methods. The influence of these properties such as phase structure, specific surface area, pore volume and so on, on the catalysts activity were studied. The results showed that specific surface area of the catalysts can directly reflect the level of activity. Adding Fe to the catalyst made the specific surface area increased, the dispersion increased, then the catalyst activity also increased.Properties of the catalyst on different reaction stages were characterized by Fourier Transform Infrared spectroscopy (FT-IR) to study the inactivation mechanism of the catalyst. The results showed that the catalyst deactivation is due to the deposition of ammonium sulfate on the catalyst and the sulphation of the metal oxides of the catalyst.In this thesis, the results showed that, the catalyst 8%Fe-10%MnOx-CeO2-/ZrO2 has excellent low-temperature activity and good thermal stability. It can be used for deNOx of flue gas with fewer SO2 at low temperature. These results provided the experimental foundation for the nano-Zirconia which applied in industrial production as the vector of SCR catalyst.