低温SCR锰基催化剂抗SO₂性能优化策略研究进展

Research Progress on Optimization Strategies for SO₂ Resistance of Low-Temperature SCR Manganese-Based Catalysts

摘要: 随着环保要求日益严格，钢铁、水泥、玻璃等非电行业烟气脱硝需求迫切，但其烟气温度低(<300℃)且含硫量高的特点使传统锰基催化剂面临严重的二氧化硫中毒失活问题。锰基催化剂虽在实验室条件下展现出优异的低温选择性催化还原(SCR)活性，但抗硫中毒能力差已成为阻碍其工业化应用的核心瓶颈。本文系统综述了低温SCR锰基催化剂抗二氧化硫中毒的最新研究进展，深入分析了二氧化硫中毒机理，包括硫酸铵盐物理覆盖导致的物理中毒和活性组分转化为MnSO₄引起的化学中毒两种微观机制。重点阐述了元素掺杂、载体优化和形貌设计三大抗中毒策略：元素掺杂方面，Fe、Ce、Ni、Co等金属掺杂可通过优先与SO₂反应或提高Mn⁴⁺比例增强抗硫性能，如Fe-Mn/TiO₂催化剂在150℃下NO_x转化率可达97.7%；载体优化方面，TiO₂、碳基材料、分子筛等不同载体的限域效应显著影响催化剂抗硫性能；形貌设计方面，纳米棒、核壳等特殊结构能有效抑制硫酸盐沉积，如MnO_x/CeO₂纳米棒催化剂可在含硫环境下稳定运行1000小时而无明显活性损失。未来研究应重点关注耐硫耐水一体化设计理念，并借助原位表征技术深入揭示抗中毒机制，为锰基催化剂的工业化应用提供理论指导。

Abstract: With the increasingly stringent requirements of environmental protection, the demand for flue gas denitrification in non-electric industries such as steel, cement and glass is urgent. However, the low temperature (<300˚C) and high sulfur content of flue gas make the traditional manganese-based catalysts face serious deactivation of sulfur dioxide poisoning. Although manganese-based catalysts exhibit excellent low-temperature selective catalytic reduction (SCR) activity under laboratory conditions, poor sulfur poisoning resistance has become a core bottleneck hindering their industrial application. This paper systematically reviews the latest research progress of low-temperature SCR manganese-based catalysts against sulfur dioxide poisoning, and deeply analyzes the mechanism of sulfur dioxide poisoning, including physical poisoning caused by physical coverage of ammonium sulfate and chemical poisoning caused by the conversion of active components into MnSO₄. The three anti-poisoning strategies of element doping, carrier optimization and morphology design are emphasized. In terms of element doping, metal doping such as Fe, Ce, Ni and Co can enhance the sulfur resistance by preferentially reacting with SO₂ or increasing the proportion of Mn⁴⁺. For example, the NO_x conversion rate of Fe-Mn/TiO₂ catalyst can reach 97.7% at 150˚C. In terms of carrier optimization, the confinement effect of different carriers such as TiO₂, carbon-based materials, and molecular sieves significantly affects the sulfur resistance of the catalyst. In terms of morphology design, special structures such as nanorods and core-shell can effectively inhibit sulfate deposition. For example, MnO_x/CeO₂ nanorod catalyst can operate stably for 1000 hours without obvious activity loss in sulfur-containing environment. Future research should focus on the integrated design concept of sulfur and water resistance, and further reveal the anti-poisoning mechanism with the help of in-situ characterization technology, so as to provide theoretical guidance for the industrial application of manganese-based catalysts.