Effect of structure and morphology on manganese-based catalysts’ sulfur and water resistance

doi:10.16085/j.issn.1000-6613.2022-0510

Abstract

Abstract:

For ammonia selective catalytic reduction (NH₃-SCR), the Mn-based catalysts have good low-temperature catalytic activity, but they are susceptible to SO₂ and H₂O. Adjusting the structural and morphology of the catalysts can effectively improve their sulfur and water resistance. Therefore, this review summarizes the research progress of Mn-based catalysts with different structures of core-shell, hollow, three-dimensional ordered porous and two-dimensional layered structure, for the sulfur and water resistance. The mechanisms of sulfur and water poisoning of Mn-based catalysts are briefly described. The effect of structure on the resistance enhancement of Mn-based catalysts is also analyzed based on the combination of poisoning mechanism and structural characteristics. This review also summarizes the preparation methods of the above four structural catalysts, and points out the development direction of industrial preparation of structural catalysts in the future. At the same time, the future research work is prospected. Suggestions such as in-depth study of synergistic poisoning mechanism, optimization of catalysts formulation via simulation are put forward, which could provide reference for improving Mn-based catalysts’ resistance and industrial preparation.

Key words: SCR, deactivation, preparation, structure, Mn-based catalyst, resistance to SO₂ and H₂O

摘要：

锰（Mn）基催化剂在氨选择性催化还原（NH₃-SCR）领域虽具有良好的低温活性，但容易受到二氧化硫和水蒸气的影响。研究发现调整催化剂的结构形貌可以有效提升催化剂的抗硫抗水性能。因此，本文综述了核壳结构、中空结构、三维有序孔道结构和二维层状结构Mn基催化剂在低温NH₃-SCR抗硫抗水领域的研究进展，简要阐述了Mn基催化剂硫水中毒机理，并结合中毒机理与结构特点分析了结构在提升Mn基催化剂抗性方面起到的作用。此外，本文还总结了以上四种结构催化剂的制备方法，并指出结构催化剂未来工业化制备的发展方向。同时，对今后研究工作进行展望，提出深入研究协同中毒机理、模拟优化催化剂配方等建议，为实现Mn基催化剂的高抗性及工业化应用提供了借鉴。

关键词: 选择催化还原, 失活, 制备, 结构, Mn催化剂, 抗硫抗水

CLC Number:

X701

LI Zhaoming, SHEN Boxiong, FENG Shuo, BIAN Yao. Effect of structure and morphology on manganese-based catalysts’ sulfur and water resistance[J]. Chemical Industry and Engineering Progress, 2023, 42(1): 226-235.

李钊铭, 沈伯雄, 封硕, 边瑶. 锰基催化剂结构形貌对催化剂抗硫抗水性能影响[J]. 化工进展, 2023, 42(1): 226-235.

Figures/Tables 11

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结构	特点	制备方法	引用文献
核壳结构	比表面积大、活性位点数量多、表面酸性强；外壳具有屏蔽作用，阻止SO₂、H₂O与活性组分接触；金属氧化物和分子筛外壳都可促进NH₄HSO₄分解，阻止沉积物覆盖活性位点；金属氧化物外壳延缓SO₂氧化，缓解活性组分硫化反应；金属外壳可作牺牲剂，捕集气相中SO₂并优先与SO₂反应，保护活性组分；分子筛外壳具有高疏水性，减少H₂O在催化剂表面的吸附	水热法；化学沉淀法；干凝胶转换法；超声处理浸渍法；化学沉淀电偶置换法	[23-28] [46-47]
中空结构	比表面积大，表面酸性强；气体扩散性好，传质效率高；具有羟基吸附位点，可锚定SO₂；曲率半径大，蒸发压强，有利于NH₄HSO₄沉淀分解	硬模板法；自组装法；溶剂热法；水热法	[11] [30-34]
三维有序孔道结构	孔径均匀、孔道排布规律整齐，增加比表面积和酸性位点；活性组分分散性强，且镶嵌在孔壁中，保护活性组分，减少团聚现象；大孔结构减小毛细作用，降低H₂O在催化剂表面吸附，提高了催化剂的耐水性	纳米铸造法；软胶体晶体模板法	[36-39] [48, 50]
LDHs衍生二维层状结构	具有独特的阴阳离子层交错结构，增强层间电子传递，促进氧化还原循环，提高催化剂活性及抗性；具有较大的比表面积，表面酸性强；分散性好，稳定性强，活性组分在催化剂表面不易团聚	共沉淀法；尿素均相沉淀法	[44-45]

结构	特点	制备方法	引用文献
核壳结构	比表面积大、活性位点数量多、表面酸性强；外壳具有屏蔽作用，阻止SO₂、H₂O与活性组分接触；金属氧化物和分子筛外壳都可促进NH₄HSO₄分解，阻止沉积物覆盖活性位点；金属氧化物外壳延缓SO₂氧化，缓解活性组分硫化反应；金属外壳可作牺牲剂，捕集气相中SO₂并优先与SO₂反应，保护活性组分；分子筛外壳具有高疏水性，减少H₂O在催化剂表面的吸附	水热法；化学沉淀法；干凝胶转换法；超声处理浸渍法；化学沉淀电偶置换法	[23-28] [46-47]
中空结构	比表面积大，表面酸性强；气体扩散性好，传质效率高；具有羟基吸附位点，可锚定SO₂；曲率半径大，蒸发压强，有利于NH₄HSO₄沉淀分解	硬模板法；自组装法；溶剂热法；水热法	[11] [30-34]
三维有序孔道结构	孔径均匀、孔道排布规律整齐，增加比表面积和酸性位点；活性组分分散性强，且镶嵌在孔壁中，保护活性组分，减少团聚现象；大孔结构减小毛细作用，降低H₂O在催化剂表面吸附，提高了催化剂的耐水性	纳米铸造法；软胶体晶体模板法	[36-39] [48, 50]
LDHs衍生二维层状结构	具有独特的阴阳离子层交错结构，增强层间电子传递，促进氧化还原循环，提高催化剂活性及抗性；具有较大的比表面积，表面酸性强；分散性好，稳定性强，活性组分在催化剂表面不易团聚	共沉淀法；尿素均相沉淀法	[44-45]

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