The stability mechanism of CO catalytic oxidation over Ru/TiO2 in the presence of SO2 and H2O

IF 8.1 1区工程技术 Q1 ENGINEERING, CHEMICAL

Separation and Purification Technology Pub Date : 2025-06-19 DOI:10.1016/j.seppur.2025.134051

Xinglong Gu, Zijun Gong, Quanlong Li, Zheng Huang, Shihao Li, Dong Zhang, Changming Li, Jianling Li, Zhaohui Chen, Jian Yu

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引用次数: 0

Abstract

Developing catalysts suitable for applications in industrial flue gas and capable of stably removing CO remains a major challenge, primarily due to catalyst deactivation in the presence of SO₂ and H₂O. This study found that the Ru/TiO₂ catalyst can remain stable for CO oxidation in the presence of SO₂ and H₂O under certain conditions (e.g., high CO concentrations, high temperatures) even though its CO oxidation activity decays at the initial stage. The multiple structural characterizations identified the increased ratio of Ru³⁺/Ru^δ+ and Ti⁴⁺/Ti³⁺ as well as notable surface sulfur species in the used Ru/TiO₂, which confirms the partial sulfation of Ru/TiO₂ after use. Particularly, TPR and in situ DRIFTS results indicate that sulfate is uniformly and easily reduced at central reduction temperatures above 250 °C. In addition, a series of DRIFTS tests further confirmed that the presence of high concentrations of CO significantly inhibited sulfate formation. CO oxidation proceeded through the generation of key intermediates such as carbonates and formates. Moreover, the presence of H₂O promoted the *OH-mediated pathway, facilitating the formation of HCOO* species and thereby suppressing further sulfate accumulation. All these structure and reaction data demonstrate that a dynamic depositional-decomposition equilibrium of surface sulfur species exists for the CO oxidation over the Ru/TiO₂ catalyst on certain conditions such as high CO concentration, elevated temperature, or low SO₂ concentration, accounting for the observed activity decay at the initial stage but subsequent durability and stability for the long-term performance test in the presence of SO₂ and H₂O. The revealed unique stability mechanism of CO catalytic oxidation over noble metal catalysts will shed light on the development of efficient and stable noble metal catalysts and accelerate their engineering application for the purification of CO from flue gas in industry.

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SO2和H2O存在下Ru/TiO2上CO催化氧化的稳定性机理

开发适用于工业烟气并能够稳定去除CO的催化剂仍然是一项重大挑战，主要原因是催化剂在SO2和H2O存在下失活。本研究发现，在一定条件下（如高CO浓度、高温），Ru/TiO2催化剂在SO2和H2O存在下，虽然其CO氧化活性在初始阶段会衰减，但仍能保持稳定的CO氧化活性。多重结构表征表明，Ru/TiO2中Ru3+/Ruδ+和Ti4+/Ti3+的比值增加，表面硫化物明显，证实了Ru/TiO2在使用后发生了部分磺化。TPR和原位DRIFTS结果表明，在250 °C以上的中心还原温度下，硫酸盐是均匀且容易还原的。此外，一系列的DRIFTS测试进一步证实，高浓度CO的存在显著抑制了硫酸盐的形成。CO氧化通过生成碳酸盐和甲酸盐等关键中间体进行。此外，H2O的存在促进了* oh介导的途径，促进了HCOO*物质的形成，从而抑制了硫酸盐的进一步积累。所有这些结构和反应数据表明，在一定条件下，如高CO浓度、高温或低SO2浓度，Ru/TiO2催化剂上的CO氧化存在表面硫种的动态沉积-分解平衡，这解释了在初始阶段观察到的活性衰减，但随后在SO2和H2O存在下的长期性能测试中耐久性和稳定性。揭示了CO在贵金属催化剂上催化氧化的独特稳定机理，将为开发高效稳定的贵金属催化剂，加快其在工业烟气CO净化中的工程应用提供参考。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Separation and Purification Technology 工程技术-工程：化工

CiteScore

14.00

自引率

12.80%

发文量

2347

审稿时长

43 days

期刊介绍： Separation and Purification Technology is a premier journal committed to sharing innovative methods for separation and purification in chemical and environmental engineering, encompassing both homogeneous solutions and heterogeneous mixtures. Our scope includes the separation and/or purification of liquids, vapors, and gases, as well as carbon capture and separation techniques. However, it's important to note that methods solely intended for analytical purposes are not within the scope of the journal. Additionally, disciplines such as soil science, polymer science, and metallurgy fall outside the purview of Separation and Purification Technology. Join us in advancing the field of separation and purification methods for sustainable solutions in chemical and environmental engineering.