Stabilizing Cu³⁺ Active Center by Intramolecular Electron Transfer for Boosting Complete Glucose Electrooxidation

The development of effective electrocatalysts for glucose (Glu) electro-conversion is highly desirable for sensing applications; however, is greatly plagued by unstable catalytic active centers during the catalytic process, leading to severe inactivation of active sites and incomplete Glu electrooxidation. Herein, we report a class of single-atom Pt-doped Cu-based metal-organic frameworks (MOFs) with stable high-valence Cu sites (CuO-MOF-Pt₁), achieving a complete oxidation of Glu and a milliampere current response toward Glu. We demonstrate that the -CN of MOF and Pt serve as electron-withdrawal sites to induce electron transfer of the Cu site, promoting the electrochemical generation of the stabilized Cu³⁺ active center. Using operando spectroscopy and computation, we uncover that a complete glucose electrooxidation reaction (GOR) can be achieved by successive C─C bond scission over CuO-MOF-Pt₁, and a stable Cu³⁺ active center is responsible for its impressive GOR activity. Notably, CuO-MOF-Pt₁ delivers comparable Glu sensing performance with a high sensitivity of 2.587 mA mM^-1 cm^-2, a low detection limit of 0.93 µM, and extraordinary durability. We further constructed a miniaturized CuO-MOF-Pt₁-based sensor, enabling accurate detection of Glu in saliva. This work opens an inspiring avenue to the precise design of stable metal activity centers through electronic structure regulation for boosting Glu electrooxidation.