Fe and Mn mixed oxide catalysts supported on Sn-modified TiO2 for the selective catalytic reduction of NO with NH3 at low temperature
Fe and Mn mixed oxide catalysts supported on Sn-modified TiO2 for the selective catalytic reduction of NO with NH3 at low temperature
复制标题
Sn改性TiO2负载的Fe和Mn混合氧化物催化剂用于低温下NH3选择性催化还原NO
DOI：
10.1039/d1nj05290j
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发表时间：
2021
影响因子：
3.3
通讯作者：
潘新祥
中科院分区：
文献类型：
--
作者：
韩志涛;杜还;徐朵;高宇;杨少龙;宋立国;董景明;潘新祥
虽然FeMn/TiO 2催化剂具有良好的低温活性，但其抗SO2性能差仍然是一个严重的问题。本报告探讨了使用Sn作为添加剂来改性TiO 2载体的FeMn/SnxTiO 2催化剂的合成具有优异的抗SO2。结果表明，Sn的掺杂可以显著提高TiO 2的抗SO2能力和低温SCR活性。当Sn/Ti摩尔比大于0.05时，FeMn/SnxTiO 2中TiO 2晶相由金红石型完全转变为金红石型，增强了介孔结构的稳定性。FeMn/Sn0.05TiO2-S催化剂在3 h的抗SO2试验后仍具有较高的比表面积。H2-TPR、XPS和TG结果表明，Sn的掺杂改善了材料的氧化还原性能，提高了材料中Mn ~（4+）和表面化学吸附氧的含量，有利于提高材料的低温活性。此外，Sn掺杂还能有效抑制FeMn/Sn 0. 05 TiO 2催化剂表面硫酸盐的生成。原位漫反射红外光谱结果表明，Sn掺杂能明显抑制SO2在FeMn/Sn 0. 05 TiO 2催化剂表面的吸附。同时，促进了NH3物种在刘易斯酸中心上的吸附，有利于提高催化剂的低温活性。在Sn改性的FeMn/TiO 2催化剂上，由于SO2和NH3在活性位上的相互作用和相对吸附被消除，SCR反应遵循E-R机理，通过接近正常的反应途径进行。
Although FeMn/TiO2 catalysts possessed a good low-temperature activity, their poor SO2 resistance remained a serious issue. This report explores the use of Sn as an additive to modify TiO2 supports for the synthesis of FeMn/SnxTiO2 catalysts with excellent SO2 resistance. The results showed that the doping of Sn in TiO2 could improve the SO2 tolerance and low-temperature SCR activity significantly. When the Sn/Ti molar ratio was higher than 0.05, the crystal phase of TiO2 in FeMn/SnxTiO2 was transformed from anatase to rutile completely, which enhanced the stability of the mesoporous structure. The FeMn/Sn0.05TiO2-S catalyst possessed a relatively high specific surface area even after exposure to the SO2 resistance test for 3 h. The H2-TPR, XPS and TG results showed that Sn doping improved the redox properties, and the amounts of Mn4+ and surface chemisorbed oxygen, which were beneficial for improving the low-temperature activity. Furthermore, Sn doping could also effectively inhibit the formation of sulfates on the surface of the FeMn/Sn0.05TiO2 catalyst in the SO2 resistance test. The in situ DRIFTS results revealed that Sn doping could obviously suppress SO2 adsorption on the surface of the FeMn/Sn0.05TiO2 catalyst. Meanwhile, it enhanced the adsorption of NH3 species on the Lewis acid sites, which was also beneficial for improving the low-temperature activity. As the interactions and comparative adsorption between SO2 and NH3 on the active sites had been allivated, this resulted in the SCR reactions proceeding via the Eley–Rideal (E–R) mechanism through a nearly normal pathway over the Sn-modified FeMn/TiO2 catalyst.