Complete Glucose Electrooxidation Enabled by Coordinatively Unsaturated Copper Sites in Metal-Organic Frameworks

The electrocatalytic oxidation of glucose plays a vital role in biomass conversion, renewable energy, and biosensors, but significant challenges remain to achieve high selectivity and high activity simultaneously. In this study, we present a novel approach for achieving complete glucose electrooxidation utilizing Cu-based metal-hydroxide-organic framework (Cu-MHOF) featuring coordinatively unsaturated Cu active sites. In contrast to traditional Cu(OH)₂ catalysts, the Cu-MHOF exhibits a remarkable 40-fold increase in electrocatalytic activity for glucose oxidation, enabling exclusive oxidation of glucose into formate and carbonate as the final products. The critical role of open metal sites in enhancing the adsorption affinity of glucose and key intermediates was confirmed by control experiments and density functional theory simulations. Subsequently, a miniaturized nonenzymatic glucose sensor was developed showing superior performance with a high sensitivity of 214.7 μA mM^-1  cm^-2 , a wide detection range from 0.1 μM to 22 mM, and a low detection limit of 0.086 μM. Our work provides a novel molecule-level strategy for designing catalytically active sites and could inspire the development of novel metal-organic framework for next-generation electrochemical devices.