Cu2O Nanostructures Formed by Potential-Controlled Dissolution-Redeposition of Layered Copper Hydroxide for Nonenzymatic Glucose Detection

Abstract

In this study, we describe the importance of the morphology of copper oxide nanostructures for glucose detection. To evaluate the morphological effect on glucose detection, we adopted a single copper source of layered copper hydroxide as a precursor and synthesized a variety of copper(I) oxide (Cu₂O) nanostructures on the carbon paper through dissolution-redeposition reactions by varying the applied potential at −0.8, −1.2, and −1.6 V versus Ag/AgCl. Scanning electron microscopy and X-ray photoelectron spectroscopy analysis confirmed that the resultant deposits showed three Cu₂O nanostructures (cluster-, whisker-, and particle-shaped) with nearly identical chemical structures. Such morphological differences critically affect the electrochemical properties for glucose detection. The whisker-shaped Cu₂O electrode exhibited the best sensitivity, detection range, and long-term stability. This was due to the low electrochemical reaction resistance induced by the large active surface area, as confirmed by cyclic voltammetry and electrochemical impedance spectroscopy. This work provides crucial insights into the fundamental understanding of morphological effects for increasing glucose detection capability.