Electric Power Technology and Environmental Protection

【目的】核壳结构催化剂因其独特的结构和化学特性在选择性催化还原(selective catalytic reduction，SCR)领域受到了广泛关注，因此需充分了解核壳结构催化剂的性能与机理，为燃气轮机高温尾气脱硝提供重要的技术支撑。【方法】本文在对燃气轮机高温污染现状和脱硝技术作简要介绍的基础上，系统综述了核壳结构催化剂在高温中SCR的研究进展。重点总结了金属氧化物基和分子筛基核壳催化剂的制备方法、结构特性及其在高温SCR中的性能表现。通过分析核壳界面协同效应、梯度孔道传质优化及物理化学屏障作用，揭示了其性能提升的内在机制。【结果】结果表明，核壳结构催化剂通过核壳界面协同、空间限域和功能分区等机制，显著提升了高温SCR性能。金属氧化物基核壳催化剂(如CeO₂@TiO₂)通过增强界面氧空位浓度和物理屏障作用，提高了NOx转化率和抗硫中毒能力，有研究表明SiO2修饰使催化剂在250~400 ℃的NOx转化率提升12%，在体积含量为5×10~-5SO2和10%H2O的烟气中，活性保持率从传统催化剂的58%提升至89%；分子筛基核壳催化剂通过梯度孔道设计和双金属协同作用，实现了宽温度窗口(200~550 ℃)下的高活性和高稳定性，K+交换的Cu/SAPO-34核与Fe/Beta壳层结合，协同实现H2O/CO2共存下的高稳定性，NOx转化率大于95%。Fe-Cu双金属SSZ-13中Fe~3+与Cu~2+的协同作用可拓宽温度窗口至200~550 ℃，NOx转化率大于90%。核壳结构还能有效抑制碱金属、SO₂、H₂O等毒化物质对活性位点的侵蚀，延长催化剂寿命。【结论】未来研究应聚焦于核壳界面动态演变机理的原位表征、复杂烟气环境下催化剂的耐受性机制研究，以及从实验室粉体催化剂向整体式催化剂的工程转化，推动核壳催化剂在燃气轮机高温SCR系统中的规模化应用。

[Objective]Core-shell structured catalysts have garnered widespread attention in the field of selective catalytic reduction (SCR) due to their unique structural and chemical properties. Therefore, it is essential to thoroughly understand the performance and mechanisms of core-shell catalysts to provide crucial technical support for denitrification of high-temperature exhaust gases from gas turbines. [Methods] Based on a brief introduction to the current status of high-temperature pollution from gas turbines and denitrification technologies, this paper systematically reviews the research progress of core-shell structured catalysts in high-temperature SCR. It focuses on summarizing the preparation methods, structural characteristics, and performance of metal oxide-based and zeolite-based core-shell catalysts in high-temperature SCR. By analyzing the synergistic effects at the core-shell interface, optimization of mass transfer in gradient pore channels, and the role of physicochemical barriers, the intrinsic mechanisms for performance enhancement are elucidated. [Results] The results indicate that core-shell structured catalysts significantly enhance high-temperature SCR performance through mechanisms such as core-shell interfacial synergy, spatial confinement, and functional zoning. Metal oxide-based core-shell catalysts (e.g.,CeO₂@TiO₂ ) improve NOx conversion and resistance to sulfur poisoning by enhancing interfacial oxygen vacancy concentration and physical barrier effects. Studies show that SiO2 modification increases the NOx conversion rate by 12% at 250-400 °C, and the activity retention rate in flue gas containing 5×10~-5SO2 and 10%H2O improves from 58% for conventional catalysts to 89%. Zeolite-based core-shell catalysts achieve high activity and stability over a wide temperature window (200-550 °C) through gradient pore design and bimetallic synergy. For instance, the combination of K+ exchanged Cu/SAPO-34 core with Fe/Beta shell synergistically ensures high stability in the presence of H2O/CO2 , with NOx conversion exceeding 95%. The synergy between Fe~3+ and Cu~2+ in Fe-Cu bimetallic SSZ-13 broadens the temperature window to 200-550 ℃, with NOx conversion exceeding 90%. The core-shell structure also effectively inhibits the erosion of active sites by toxic substances such as alkali metals,SO2 and H2O, thereby extending the catalyst lifespan. [Conclusion] Future research should focus on the in situ characterization of the dynamic evolution mechanisms at the core-shell interface, investigations into the tolerance mechanisms of catalysts under complex flue gas environments, and the engineering transition from laboratory powder catalysts to monolithic catalysts, to promote the large-scale application of core-shell catalysts in high-temperature SCR systems for gas turbines.