| In recent years,along with the improving living and production standard,air pollution is becoming more and more serious.The mainly pollutant is NOx.Removing NOx from stationary sources has drawn much attraction in the environmental field.As the NH3-SCR has been an important technology of the removal of NOx,the development of NH3-SCR catalysts has reasonably been the most significant task in this process.The main research contents are as follows:1.Mn2O3-doped Fe2O3 hexagonal microsheets were prepared via a hydrothermal synthesis method.These hexagonal microsheets were shown to exhibit a considerable uniform hexagonal microsheet structure and excellent low temperature SCR efficiency.When doped with different Mn molar ratios,Mn2O3 was detected in the Fe2O3hexagonal microsheets based on the XRD results without the presence of other MnOx species.A Mn/Fe molar ratio of 0.2 showed the best SCR removal performance among the materials,where a 98%NO conversion ratio at 200°C at a space velocity of 30 000h-11 was obtained.Meanwhile,excellent tolerances to H2O and SO2,as well as high thermal stability,were obtained in Mn2O3-doped Fe2O3 hexagonal microsheets.Moreover,based on the XPS and in situ DRIFT results,it can be suggested that coupled Mn2O3 nanocrystals played a key role at low temperatures and produced a possible redox reaction mechanism in the SCR process.2.A series of highly ordered mesoporous CexZr1-xO2 were fabricated for NH3-SCR of NO using KIT-6 as a hard template,showing superior composite crystal microstructure,uniform mesopore diameter and larger surface area.Mesoporous Ce0.67Zr0.33O2 showed the best NH3-SCR activity to clean NOX,and 100%NO conversion ratio at 325°C can be reached,as well as excellent H2O or SO2 tolerance and best thermal stability.Furthermore,the addition of ZrO2 content enhanced the thermal performance and redox ability of mesoporous Cex Zr1-xO2,which were favorable for their excellent NH3-SCR performance. |
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