Facet engineering of Cu₂O for efficient electrochemical glucose sensing

Accurate monitoring glucose level is significant for human health management, especially in the prevention, diagnosis, and management of diabetes. Electrochemical quantification of glucose is a convenient and rapid detection method, and the crucial aspect in achieving great sensing performance lies in the selection and design of the electrode material. Among them, Cu₂O, with highly catalysis ability, is commonly used as electrocatalyst in non-enzymatic glucose sensing. This feature has attracted great attentions for improving sensing performances by increasing exposed surface area and modifying with other active materials, but the intrinsic electrochemical activity of Cu₂O is often diminished.

In this work, we synthesized Cu₂O cubes with exposed (100) faces, Cu₂O octahedron with exposed (111) faces and Cu₂O rhombic dodecahedron with exposed (110) faces of similar sizes to investigate the influence of expose facets on its glucose sensing performance. By employing the facets-regulation strategy, the anti-interference performance was largely improved by the Cu₂O octahedron when compared with the Cu₂O cube and the Cu₂O rhombic dodecahedron, while the sensitivity and stability were also improved. Eventually, the Cu₂O octahedron with exposed (111) faces based on glucose sensor displayed great practicability in human serum and the relative deviation was less than 3 % when compared with biochemical analyzer. Experimental, calculation and simulation result elucidate that Cu₂O octahedron with exposed (111) faces, possessing stronger intrinsic electrochemical activity, comparatively favors the glucose adsorption, electron transfer and current density enhancement, rather than more active sites.

This work focuses on the exploration of the intrinsic electrochemical activity of Cu₂O and confirms that a facets-regulation strategy is an effective approach for boosting performance of non-enzymatic electrochemical sensors, especially for their sensitivity and selectivity. Moreover, it will lay the foundation for advancing the key field of precision medicine.