Towards Functionality and Deactivation of Metal‐Single‐Atom in Heterogeneous Photocatalysts

Abstract Single‐atom heterogeneous catalysts (SAHCs) provide an enticing platform for understanding catalyst structure–property–performance relationships. The 100% atom utilization and adjustable local coordination configurations make it easy to probe reaction mechanisms at the atomic level. However, the progressive deactivation of metal‐single‐atom (MSA) with high surface energy leads to frequent limitations on their commercial viability. This review focuses on the atomistic‐sensitive reactivity and atomistic‐progressive deactivation of MSA to provide a unifying framework for specific functionality and potential deactivation drivers of MSA, thereby bridging function, purpose‐modification structure–performance insights with the atomistic‐progressive deactivation for sustainable structure–property–performance accessibility. The dominant functionalization of atomically precise MSA acting on properties and reactivity encompassing precise photocatalytic reactions is first systematically explored. Afterward, a detailed analysis of various deactivation modes of MSA and strategies to enhance their durability is presented, providing valuable insights into the design of SAHCs with deactivation‐resistant stability. Finally, the remaining challenges and future perspectives of SAHCs toward industrialization, anticipating shedding some light on the next stage of atom‐economic chemical/energy transformations are presented.