Facet engineering of Cu2O for efficient electrochemical glucose sensing

Background: 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. Result: 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. Significance and novelty: 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.