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    贵金属负载催化剂用于CO氧化研究进展

    Research Progress on CO Oxidation with Supported Noble Metal Catalysts

    • 摘要: 钢铁烧结烟气中一氧化碳(CO)的过度排放对地区空气质量和人体健康构成了严重的威胁。贵金属负载催化剂因其催化效率高、耐水抗硫性能好,在CO催化净化中受到了广泛的关注。然而,贵金属的稀缺性和昂贵价格以及复杂的烟气组分,限制了其在工业烟气治理领域的应用。因此,基于CO氧化的相关研究来指导降低贵金属负载量和提高催化剂抗中毒性能尤为重要。在现有文献的基础上,首先分析了典型贵金属负载催化剂在CO催化氧化领域的应用情况。其次,探究了制备方法、贵金属分布状态和配位环境等物化性质,以及H2O和SO2对CO催化性能的影响。随后,总结了贵金属负载催化剂上的CO反应机理。最后,展望了贵金属负载催化剂催化氧化CO方面的未来研究方向,以期为开发适用于烧结烟气的CO贵金属负载催化剂的优化设计提供指导。

       

      Abstract: The excessive emission of carbon monoxide (CO) from steel sintering flue gas poses a significant threat to regional air quality and human health. This necessitates the development of effective CO treatment technologies for sintering flue gas. Among these, catalytic oxidation technology has emerged as a stable and efficient method for CO removal. Noble metal-loaded catalysts, including those based on platinum (Pt), palladium (Pd), gold (Au), ruthenium (Ru), and iridium (Ir), are considered to have significant application potential due to their excellent low-temperature oxidation performance and resistance to water and sulfur. However, challenges arise from the scarcity and high cost of noble metals, as well as the complex composition of flue gases. These factors complicate the application of noble metal-loaded catalysts in industrial settings, highlighting the importance of research focused on CO oxidation. The activity of noble catalysts is primarily influenced by their physicochemical properties, including morphology, particle size, elemental doping, support type, oxygen vacancies, and surface hydroxyl groups. It has been observed that a moderate amount of H2O can enhance CO oxidation on these catalysts, while excessive H2O can inhibit the reaction due to competitive adsorption effects. Additionally, the presence of SO2 in the flue gas can lead to its adsorption on noble metal active sites or the support, further diminishing the adsorption efficiency of CO and O2 and causing carrier sulfation. The CO oxidation reaction on noble metal-loaded catalysts is governed by three mechanisms: Langmuir-Hinshelwood (L-H), Mars-van Krevelen (MvK), and Eley-Rideal (ER). H2O plays a dual role in these pathways, enhancing CO catalytic oxidation in some cases while inhibiting it in others. However, the presence of SO2 typically reduces the adsorption performance of CO and O2, which can lead to decreased catalyst activity or even deactivation. Given the emission characteristics of sintering flue gas, future research on noble metal-supported catalysts should focus on three aspects. (1) Improving stability and anti-poisoning performance: Even after desulfurization, sintering flue gas contains residual SO2, necessitating catalysts that can withstand such conditions; (2) Investigating activity in complex pollutant environments: Research should explore the activity of noble metal-based catalysts in the presence of various pollutants, including SO2, heavy metals, alkali metal dust, and chlorine-containing VOCs; (3) Reducing noble metal loading: Given the high flow rates of sintering flue gas, it is crucial to develop strategies that minimize noble metal usage while maintaining effective CO treatment. This paper aims to provide guidance for the development and optimization design of CO noble metal supported catalysts for sintering flue gas.

       

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