Three‐Electron Uric Acid Oxidation via Interdistance‐Dependent Switching Pathways in Correlated Single‐Atom Catalysts for Boosting Sensing Signals

The overly simplistic geometric and electronic structures of single‐atom catalysts have become a significant bottleneck in the field of single‐atom sensing, impeding both the design of highly efficient electrochemical sensors and the establishment of structure‐activity relationships. To address these challenges, we present a novel strategy to boost the sensing performance of single‐atom catalysts by precisely tuning the single‐atomic interdistance (SAD) in correlated single‐atom catalysts (c‐SACs). A series of Ru‐based c‐SACs (Rud=6.2 Å, Rud=7.0 Å, and Rud=9.3 Å) are synthesized with predetermined SAD values, which are comprehensively characterized by various techniques. Electrochemical studies on uric acid (UA) oxidation reveal that Rud=6.2 Å demonstrates an extraordinary sensitivity of 9.83 μA μM‐1cm‐2, which is superior to most of electrochemistry biosensors reported previously. Kinetic analysis and product examination unveil that the 6.2 Å Ru SAD instigates a distinctive three‐electron oxidation of UA, with an extra electron transfer compared to the conventional two‐electron pathway, which fundamentally enhances its sensitivity. Density functional theory calculations confirm the optimal SAD facilitates dual‐site UA adsorption and accelerated charge transfer dynamics. This investigation provides novel insights into the strategic engineering of high‐performance SAC‐based electrochemical sensors by precisely controlling the atomic‐scale structure of active sites.