Coordination‐Modulated Catalytic Pathways at Carbon Dots‐Supported Single‐Atom Sites Revealed by Thiol Interactions

Understanding how coordination environments regulate catalytic pathways at single‐atom sites is central to the rational design of advanced catalysts. Here, we report a general room‐temperature strategy for constructing carbon dots‐supported single‐atom catalysts (M SACs@CDs; M = Ru, Pt, and Pd), enabling uniform atomic dispersion within nitrogen‐rich coordination frameworks. Using Ru SACs@CDs as a model system, combined spectroscopic characterization and density functional theory calculations reveal a well‐defined Ru–N 4 coordination environment that governs H 2 O 2 activation and reactive oxygen species (ROS) generation. We show that thiol coordination at Ru centers induces pronounced electronic perturbations that reshape the reaction energy landscape. Rather than simple active‐site blocking, such coordination dynamically modulates key elementary steps, including H 2 O 2 adsorption, O─O bond cleavage, and the relative contributions of the hydroxyl radical (•OH) and singlet oxygen ( 1 O 2 ) pathways. Distinct coordination modes of structurally similar thiols therefore lead to differentiated catalytic responses, providing a direct experimental handle for probing pathway‐level variations. These findings establish a coordination‐modulated catalytic mechanism in which substrate binding actively reconfigures reaction pathways at single‐atom sites. This work advances a general framework for linking coordination chemistry with catalytic reactivity, offering new design principles for single‐atom catalysts with tunable and programmable functionalities.