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 (Ru_{d=6.2 Å}, Ru_{d=7.0 Å}, and Ru_{d=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 Ru_{d=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.