Abstract: A catalyst of iron manganese oxides supported on mesoporous silica (MPS), Mn-Fe/MPS, was prepared and applied for selective catalytic reduction (SCR) of NO with ammonia in the presence of excessive oxygen at low temperatures. The effects of H2O and SO2 on the catalyst were studied. The results showed that a 99.1% NO conversion rate at 433 K at a space velocity of 20000 h-1 was achieved with the catalyst. H2O (10%, j) had not negative impact on the activity when the SCR reaction temperature was above 413 K and the NO SCR conversion rate could exceed 97.8%. A 97.2% NO conversion rate at 443 K in the presence of low concentration of SO2 (100′10-6) was obtained with the catalyst. In addition, as the SCR reaction proceeded in the presence of H2O and SO2, the catalyst was deactivated gradually, but its activity could almost be recovered to the initial level after heat treatment at 773 K, and the FT-IR spectra showed that the ammonium sulfate formed during SCR reaction in the presence of the H2O and SO2. Improving the SCR temperature could slow down the deactivation of catalyst. The effect of heat treatment temperature on the deactivated catalyst was also studied, and the recovery mechanism of the catalyst discussed. The prepared catalyst is substantially superior to any other reported catalysts in the literature in terms of integrated performance.

Key words: selective catalytic reduction of NO, mesoporous silica, Mn, Fe, H2O, SO2

摘要： 研究了H2O和SO2对Mn-Fe/MPS催化剂低温下选择性催化NH3还原(SCR)NO的影响. 结果表明，Mn-Fe/MPS催化剂具有良好的催化活性，在空速为20000 h-1、反应温度433 K时，NO的SCR转化率达99.1%. 在反应温度低于413 K时，水蒸汽(10%, j)在一定程度上降低了催化活性；超过433 K时，这种影响可完全消除，NO的SCR转化率达到97.8%以上. 低浓度SO2(100′10-6)存在条件下，443 K时催化效率仍可稳定在97.2%. 在水和SO2共存的情况下，生成的硫酸盐和亚硫酸盐沉积在催化剂表面导致催化剂逐渐失活，FT-IR测试也表明伴随SCR反应生成了硫酸铵. 提高反应温度可以延缓催化剂的失活. 此外还研究了不同活化温度对催化剂活性恢复的影响，结果表明，当活化温度达到773 K时，催化剂活性可以完全恢复. 本研究中的催化剂的综合性能优于目前文献报道的其他催化剂.

关键词: NO选择性催化还原, 介孔二氧化硅, 锰, 铁, H2O, SO2