Spin‐State Regulation of Single‐Atom Catalysts: From Quantum Mechanisms to Multidimensional Dynamic Regulation Strategies

Abstract Single‐atom catalysts (SACs) have emerged as a research hotspot in clean energy technology due to their atomic‐level metal dispersion and near‐100% utilization rate, but they face critical spin‐state‐related issues, including spin‐forbidden reactions from mismatched spin symmetry, suboptimal intermediate adsorption caused by coordination‐limited electronic structures, and spin‐driven agglomeration leading to deactivation. This review focuses on the role of spin‐state regulation in addressing these challenges. It elaborates on the quantum mechanisms underlying spin‐state‐related effects, including crystal field theory, spin exchange interaction, spin polarization, spin crossover, spin‐orbit coupling, as well as the synergism mechanisms of spin‐state‐related effects and charge transfer, etc. The review systematically discusses multidimensional dynamic regulation strategies, including coordination environment engineering, external field modulation, and support engineering, which synergistically tune the spin state of single atoms to optimize catalytic activity, selectivity, and stability. Furthermore, the challenges, including unclear dynamic spin evolution mechanisms and limitations of characterization techniques, and perspectives, including multi‐physics field synergy, are highlighted. Spin‐state regulation in SACs not only deepens the understanding of catalytic nature but also provides a new paradigm for designing next‐generation efficient and stable SACs, promoting their applications in clean energy conversion.