Fe-PILC在贫燃条件下催化丙烯选择性还原NO

采用羟基铁离子柱撑Na-Mont制备了铁柱撑黏土催化剂(Fe-PILC),铁物种作为柱撑成分,同时充当活性组分,研究其在贫燃条件下催化丙烯选择性还原NO的特性。通过XRD、N_2吸附-脱附、H_2-TPR、UV-vis、Py-FTIR等方法对催化剂进行物理化学性质表征,进一步研究其反应机理。研究表明,1.0Fe-PILC在450-600℃时NO的转化率超过98%,N_2的选择性可达97%以上,且抗水蒸气和SO_2的能力较强。XRD和N_2吸附-脱附研究表明,Fe-PILC中铁物种柱撑进入Na-Mont层间,使催化剂的比表面积和孔容增大。H_2-TPR研究表明,Fe-PILC在400℃左右还原能力较强,主要体现为Fe~(3+)→Fe~(2+)的还原。UVvis研究表明,Fe-PILC的脱硝活性与铁氧低聚物种FexOy呈正相关。Py-FTIR研究表明,Fe-PILC表面同时含有Lewis酸和Br■nsted酸性位,Lew is酸性位是C_3H_6与NO进行催化反应的主要活性中心。

Fe-PILC for selective catalytic reduction of NO by propene under lean-burn conditions

Iron-pillared clays (Fe-PILC) were prepared by ion-exchange method and the iron species act as the pillaring components and active components and their performances for selective catalytic reduction of NO by propene were investigated under lean-burn conditions. XRD, N₂ adsorption/desorption, H₂-TPR, UV-vis, Py-FTIR, etc were used to characterize the catalysts. The results showed that 1.0Fe-PILC reduced more than 98% of NO at 450-600℃ and the selectivity for N₂ reached 97%. The catalytic activity of the 1.0Fe-PILC was slightly influenced by water vapor and SO₂. XRD and N₂ adsorption/desorption characterization results showed that the iron species entered the Na-Mont interlayer and formed much larger specific surface area and pore volume. H₂-TPR results indicated that Fe-PILC had a strong reduction ability at about 400 ℃, which represented the reduction of Fe³⁺→Fe²⁺. UV-vis results showed that the denitrification activity of Fe-PILC was positively correlated with the iron oxide oligomer Fe_xO_y. Py-FTIR results revealed that Lewis acid and Brønsted acid sites formed on the Fe-PILC surface. The main catalytic activity center of C₃H₆ and NO reaction was the Lewis acid site.