Synergistic Coordination Effect and Metal‐Support Interaction Engineering of Single‐Atom Mn–N₂ Sites for Boosting Sensitive and Selective Dopamine Biosensing in Human Serum

Abstract Coordination environment of metal atoms is core for designing high‐performance single‐atom catalysts (SACs), while metal‐support interaction also has an important effect on structure‐function relationship. Nevertheless, the interaction effect of metal‐support is mostly ignored. Through synergistic regulation of coordination environment and metal‐support interaction, Mn SAC with atom‐dispersed Mn–N₂ sites on dopamine (DA) support is synthesized for sensitive and selective DA oxidation based on theoretical calculations and experimental explorations. MnN₂ presents the more optimal catalytic site for DA oxidation than other coordination conditions, enhancing sensitivity including a wide range, a low limit of detection, and particularly a very low catalytic potential. The construction of Mn–N₂ active sites on DA carbon promotes the coupling between Mn metal atoms and DA support, decreasing work function, facilitating electron exchange, shortening response time, and boosting selectivity. Both the catalytic mechanism of Mn SAC toward DA and the relation construction of catalyst's structure and catalytic function are established.