Scholarlink

<p>For the working conditions with large fluctuations in flue gas temperature during actual operation, developing NH<sub>3</sub>-SCR catalysts with high activity and a wide temperature window is of great significance for the control of low-temperature NO<sub>x</sub> emissions. To further broaden the active temperature range of the Fe–Ce–Mn/TiO<sub>2</sub> catalyst, a series of Fe–Ce–Mn/TiO<sub>2</sub> catalysts with different amounts of polyethylene oxide (PEO) were prepared via the co-precipitation method. The results show that the introduction of PEO significantly broadens the catalyst’s active temperature window. The catalyst with 3.75% PEO achieved over 90% NO conversion across a wide temperature range of 121–386&#xa0;°C. Moreover, long-term stability and poisoning-resistance tests demonstrated that FeCeMnTi-3.75 maintained higher NO conversion than the unmodified catalyst during 100&#xa0;h operation in the presence of H<sub>2</sub>O and SO<sub>2</sub>, indicating improved operational stability and tolerance under simulated industrial conditions. Characterization analysis shows that an appropriate amount of PEO as a pore-forming agent can not only effectively inhibit the agglomeration of active components and increase the specific surface area of the catalyst, but also significantly increase the relative proportions of Fe<sup>2+</sup>, Ce<sup>3+</sup>, Mn<sup>4+</sup>, and the content of surface adsorbed oxygen. This structural and chemical synergy enhances redox ability and surface acidity of the catalyst. In situ DRIFTS results suggest that the NH<sub>3</sub>-SCR reaction over both catalysts may involve the coexistence of L–H and E–R pathways. PEO modification does not appear to fundamentally change the reaction mechanism, but it affects the adsorption strength, relative abundance, and transformation behavior of surface NH<sub>3</sub> and NO<sub>x</sub> species. In particular, bidentate nitrate species may serve as important reactive intermediates in the L–H pathway, while the faster attenuation of pre-adsorbed NO<sub>x</sub> species after NH<sub>3</sub> introduction indicates improved apparent surface reactivity related to the E–R pathway.</p> Graphical abstract <p></p>

错误：搜索内容不能为空，请输入英文关键词
错误：关键词超出字数限制，请精简
高级检索

Regulation mechanism of polyethylene oxide on the surface acidity and redox properties of Fe–Ce–Mn/TiO2 catalyst

  • 期刊论文

  • 发表日期：

    2026年6月28日

查看全文
  • Xuewen Mu,
  • Xue Bian,
  • Yuming Yang,
  • Yanping Li,
  • Yuting Bai,
  • Meng Zha,
  • Jing Wei,
  • Yu Huang

摘要

For the working conditions with large fluctuations in flue gas temperature during actual operation, developing NH3-SCR catalysts with high activity and a wide temperature window is of great significance for the control of low-temperature NOx emissions. To further broaden the active temperature range of the Fe–Ce–Mn/TiO2 catalyst, a series of Fe–Ce–Mn/TiO2 catalysts with different amounts of polyethylene oxide (PEO) were prepared via the co-precipitation method. The results show that the introduction of PEO significantly broadens the catalyst’s active temperature window. The catalyst with 3.75% PEO achieved over 90% NO conversion across a wide temperature range of 121–386 °C. Moreover, long-term stability and poisoning-resistance tests demonstrated that FeCeMnTi-3.75 maintained higher NO conversion than the unmodified catalyst during 100 h operation in the presence of H2O and SO2, indicating improved operational stability and tolerance under simulated industrial conditions. Characterization analysis shows that an appropriate amount of PEO as a pore-forming agent can not only effectively inhibit the agglomeration of active components and increase the specific surface area of the catalyst, but also significantly increase the relative proportions of Fe2+, Ce3+, Mn4+, and the content of surface adsorbed oxygen. This structural and chemical synergy enhances redox ability and surface acidity of the catalyst. In situ DRIFTS results suggest that the NH3-SCR reaction over both catalysts may involve the coexistence of L–H and E–R pathways. PEO modification does not appear to fundamentally change the reaction mechanism, but it affects the adsorption strength, relative abundance, and transformation behavior of surface NH3 and NOx species. In particular, bidentate nitrate species may serve as important reactive intermediates in the L–H pathway, while the faster attenuation of pre-adsorbed NOx species after NH3 introduction indicates improved apparent surface reactivity related to the E–R pathway.

Graphical abstract