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<p>Sulfation of active sites and competitive SO<sub>2</sub> adsorption critically limit the durability of NH<sub>3</sub>-SCR catalysts for industrial NO<sub>X</sub> abatement. Here, we investigate Iron (Fe) and Praseodymium (Pr) doped CeMnO<sub>X</sub> catalysts synthesized via an acid-etching-assisted hydrothermal method, focusing on mechanistic differentiation of Fe-doped catalysts’ sulfur resistance function. The Fe-doped catalyst achieves &gt; 95% NO conversion for 20&#xa0;h at 200&#xa0;°C under 50&#xa0;ppm SO<sub>2</sub>, while maintaining oxygen mobility (O<sub>β</sub>/O<sub>α</sub> ratio decreased from 89.02% to 70.29%) and enhanced surface acidity (1.10 → 2.60&#xa0;mmol&#xa0;g<sup>−1</sup>). Staged in situ DRIFTS reveals that surface-bound NH<sub>4</sub><sup>+</sup> and NH<sub>3</sub> ligands, associated with Brønsted and Lewis acid sites, respectively, serve as key intermediates. Their transformation into nitrate and nitrite species confirms coexisting&#xa0;Eley–Rideal and Langmuir–Hinshelwood pathways. Co-adsorption studies demonstrate the simultaneous presence and mutual reactivity of NH<sub>3</sub> and NO<sub>X</sub> species over time. Upon SO<sub>2</sub> exposure, reactive intermediate bands remain stable, and only weakly bound sulfur-related species are transiently detected—indicating&#xa0;minimal irreversible sulfur deposition. These findings, corroborated by H₂-TPR and XPS (FeSO<sub>4</sub> formation), clarify Fe-doped catalysts’ dual-function role in preserving redox sites while mitigating sulfation. Pr dopant isolates Fe-specific behavior, decoupling redox promotion from SO<sub>2</sub> shielding. This work provides molecular-level insights for designing robust, multifunctional SCR catalysts for SO<sub>2</sub>-laden environments.</p>

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Fe/CeMnOX Catalysts with Mechanistically Decoupled Redox Promotion and Sulfation Resistance for Low-Temperature NH3-SCR

  • 期刊论文

  • 发表日期：

    2025年12月11日

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  • Shuya Rui,
  • Yaliang Ren,
  • Zhen Ye,
  • Binghui Wu,
  • Zhehao Xu,
  • Anton Nikiforov,
  • Zhiping Ye

摘要

Sulfation of active sites and competitive SO2 adsorption critically limit the durability of NH3-SCR catalysts for industrial NOX abatement. Here, we investigate Iron (Fe) and Praseodymium (Pr) doped CeMnOX catalysts synthesized via an acid-etching-assisted hydrothermal method, focusing on mechanistic differentiation of Fe-doped catalysts’ sulfur resistance function. The Fe-doped catalyst achieves > 95% NO conversion for 20 h at 200 °C under 50 ppm SO2, while maintaining oxygen mobility (Oβ/Oα ratio decreased from 89.02% to 70.29%) and enhanced surface acidity (1.10 → 2.60 mmol g−1). Staged in situ DRIFTS reveals that surface-bound NH4+ and NH3 ligands, associated with Brønsted and Lewis acid sites, respectively, serve as key intermediates. Their transformation into nitrate and nitrite species confirms coexisting Eley–Rideal and Langmuir–Hinshelwood pathways. Co-adsorption studies demonstrate the simultaneous presence and mutual reactivity of NH3 and NOX species over time. Upon SO2 exposure, reactive intermediate bands remain stable, and only weakly bound sulfur-related species are transiently detected—indicating minimal irreversible sulfur deposition. These findings, corroborated by H₂-TPR and XPS (FeSO4 formation), clarify Fe-doped catalysts’ dual-function role in preserving redox sites while mitigating sulfation. Pr dopant isolates Fe-specific behavior, decoupling redox promotion from SO2 shielding. This work provides molecular-level insights for designing robust, multifunctional SCR catalysts for SO2-laden environments.