Progress in nuclear magnetic resonance spectroscopy for the characterization of single-atom catalysts

Single-atom catalysis, as one of the forefront topics in heterogeneous catalysis, requires precise characterization of the microstructure of catalysts to significantly advance both fundamental research and practical applications. This review systematically summarizes the progress in the application of nuclear magnetic resonance (NMR) spectroscopy to address the challenges in characterizing the active-site structures of single-atom catalysts. Focusing on two main types of NMR strategies: direct spectroscopic detection (e.g., 195Pt NMR) and indirect spectroscopic detection (e.g., 17O, 31P, 27Al NMR), this article clarifies, with representative studies, the critical role of NMR in elucidating the coordination environment, formation mechanism, and dynamic evolution of single-atom sites. Furthermore, the unique advantages and existing challenges of NMR in this field are discussed. The potential of emerging techniques, such as surface-enhanced dynamic nuclear polarization (DNP), artificial intelligence (AI)-assisted analysis, and in-situ NMR, for addressing the challenges in single-atom catalysis research is also explored.