Single-atom catalysts (SACs) represent the ultimate size limit of nanoscale catalysts, combining the advantages of homogeneous and heterogeneous catalysts. SACs have isolated single-atom active sites that exhibit high atomic utilization efficiency, unique catalytic activity, and selectivity. Over the past few decades, synchrotron radiation techniques have played a crucial role in studying single-atom catalysis by identifying catalyst structures and enabling the understanding of reaction mechanisms. The profound comprehension of spectroscopic techniques and characteristics pertaining to SACs is important for exploring their catalytic activity origins and devising high-performance and stable SACs for industrial applications. In this review, we provide a comprehensive overview of the recent advances in X-ray based synchrotron radiation techniques for structural characterization and in situ/operando observation of SACs under reaction conditions. We emphasize the correlation between spectral fine features and structural characteristics of SACs, along with their analytical limitations. The development of IMST with spatial and temporal resolution is also discussed along with their significance in revealing the structural characteristics and reaction mechanisms of SACs. Additionally, this review explores the study of active center states using spectral fine characteristics combined with theoretical simulations, as well as spectroscopic analysis strategies utilizing machine learning methods to address challenges posed by atomic distribution inhomogeneity in SACs while envisaging potential applications integrating artificial intelligence seamlessly with experiments for real-time monitoring of single-atom catalytic processes.

中文翻译：

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基于 X 射线的同步辐射技术对单原子催化剂进行结构、原位和原位表征的研究进展和挑战


单原子催化剂 （SAC） 代表了纳米级催化剂的最终尺寸极限，结合了均相和非均相催化剂的优点。SAC 具有分离的单原子活性位点，表现出高原子利用效率、独特的催化活性和选择性。在过去的几十年里，同步辐射技术通过识别催化剂结构和促进对反应机理的理解，在研究单原子催化方面发挥了至关重要的作用。对 SAC 相关的光谱技术和特性的深刻理解对于探索其催化活性起源和为工业应用设计高性能和稳定的 SAC 非常重要。在这篇综述中，我们全面概述了基于 X 射线的同步辐射技术在反应条件下对 SAC 的结构表征和原位/原位观察的最新进展。我们强调了光谱精细特征与 SAC 结构特征之间的相关性，以及它们的分析局限性。还讨论了具有空间和时间分辨率的 IMST 的发展及其在揭示 SACs 的结构特征和反应机制方面的意义。此外，本文还探讨了使用光谱精细特性结合理论模拟对活性中心态的研究，以及利用机器学习方法的光谱分析策略来解决 SAC 中原子分布不均匀性带来的挑战，同时设想了将人工智能与实验无缝集成的潜在应用，以实时监测单原子催化过程。