Mn改性Fe/H-beta催化剂的低温催化分解NO_x的研究

Catalytic Performance of Fe/H-beta Catalyst Modified by Mn for NO_x Decomposition at Low Temperature

通过Mn改性制备了Fe和Mn的质量比为1且Fe和Mn的质量分数均为5%(5%Fe-5% Mn/H-beta)的催化剂,通过氢气程序升温还原(H2-TPR)比较分析了Fe-Mn/H-beta、Fe/H-beta和Mn/H-beta催化剂中Fe和Mn的化学形态,考察了O2、SO2和H2O等反应条件对Fe-Mn/H-beta催化剂低温催化分解NOx的影响.结果表明,相比Fe/H-beta和Mn/H-beta,Fe-Mn/H-beta催化剂在富氧和低温条件下具有较好的催化活性,其中623K下催化剂的活性最高,NOx的转化率达到45%左右.Fe-Mn/H-beta催化剂中Fe和Mn的共存提高了Fe2O3和MnO2的含量.氧的存在促进了NOx催化分解,水蒸气和SO2对NOx催化分解有一定的抑制作用.

Direct decomposition of NOx was investigated with 5%Fe-5% Mn/H-beta catalysts with equal weight of Mn and Fe. The chemical states of Fe and Mn in Fe-Mn/H-beta, Fe/H-beta, and Mn/H-beta catalysts were characterized by H2-TPR. The effects of O2, SO2 and H2O on decomposition of NOx at low temperature with 5%Fe-5%Mn/H-beta catalysts were examined. The results indicate that the activity of Fe-Mn/H-beta is higher than that of Fe/H-beta or Mn/H- beta at rich oxygen and low temperature from 573 K to 673 K. The maximum NOx conversion is about 45% with 5%Fe-5%Mn/H-beta at 623 K. The presence of Fe in Fe-Mn/H-beta enhances the transformation of Mn3＋ ions into Mn4＋ ions, and the addition of Mn increases the amount of Fe203 in Fe-Mn/H-beta. In addition, O2 inhibition is not observed in NOx decomposition with Fe- Mn/H-beta while the presence of H2O and SO2 inhibits the activity of Fe-Mn/H-beta.