Fe/Ti-PILC用于C_3H_6选择性催化还原NO的研究

Experimental study on selective catalytic reduction of NO by C_3H_6 over Fe/Ti-PILC catalysts

采用二氧化钛对蒙脱土进行柱撑改性后,以离子交换法制备了铁负载二氧化钛柱撑蒙脱土催化剂Fe/Ti-PILC,考察了其在富氧条件下催化C_3H_6选择性还原NO(C_3H_6-SCR)的性能。并借助N_2等温吸附-脱附、XRD、UV-vis、H_2-TPR、Py-FTIR等表征方法研究了催化剂的结构与性能之间的关系。结果表明,所制备的19Fe/Ti-PILC催化剂在400℃时即可实现到NO的完全脱除,N2选择性能够达到90%以上。且具有较好的抗水蒸气和抗SO_2的能力。N_2吸附-脱附和XRD结果显示,蒙脱土的结构被撑开,交联柱撑有效,形成了较大的比表面积和孔体积。UV-vis结果表明,催化剂的脱硝活性与铁氧低聚物种FexOy的含量有关,Py-FTIR结果表明,催化剂表面同时存在Lewis酸和Brnsted酸,Fe^(3+)负载到柱撑黏土中能够显著增加Lewis酸的含量,Lewis酸是影响催化剂脱硝活性的影响因素之一。H_2-TPR表征表明,催化剂在400℃左右有较强的还原能力,催化剂的还原能力主要体现为Fe^(3+)→Fe^(2+)的还原。

Ti-pillared interlayer clay(PILC)-based catalysts ion exchanged with Fe were prepared and used for selective catalytic reduction of NO x using propylene as the reducing agent under oxygen-rich conditions.The relationship between structure and properties of the catalysts was studied using N 2-adsorption/desorption,XRD,UV-vis,H 2-TPR,and Py-FTIR.The results show that the prepared 19Fe/Ti-PILC catalyst can achieve complete removal of NO at 400℃,and N 2 selectivity can reach over 90%and has better resistance to water vapor and SO 2.N 2-isothermal adsorption/desorption and XRD results show that structure of montmorillonite is opened,cross-linked pillars are effective,and a large specific surface area and pore volume are formed.UV-vis results show that the denitrification activity of the catalyst is related to content of oligomeric Fe x O y.Py-FTIR results show that both Lewis acid and Br nsted acid are presented on the catalyst surface.Fe 3+loading into the pillared clay can significantly increase the Lewis acid content.Lewis acid is one of the influencing factors on the denitrification activity of the catalyst.H 2-TPR indicates that the catalyst has a strong reduction ability at about 400℃,and the reduction ability of the catalyst is mainly represented by the reduction of Fe 3+→Fe 2+.