Cavitation regulated sonochemical synthesis of flexible self-supported CuO@PDA/CC electrode for highly sensitive glucose sensor

Sonochemical synthesis is recognized as a promising high-efficiency method for fabricating transition metal oxides (TMOs) based flexible self-supported electrodes as nonenzymatic glucose sensor. However, it is still a challenge to obtain TMOs self-supported electrodes with well-controlled TMOs nanostructure and desirable interfacial properties via a sonochemical approach because of the uncontrollability of transient cavitation. In this study, CuO@polydopamine (PDA) nanoparticles (NPs) are in situ grown onto carbon cloth (CC) to fabricate CuO@PDA/CC self-supported electrode via a sonochemical process. The sonochemically synthesized PDA not only stabilized the transient cavitation intensity, but also regulated the growth of CuO due to the strong chelating ability between Cu²⁺ and catechol groups from PDA. It is determined that the mean size of CuO@PDA NPs on the CuO@PDA/CC electrode is less than 100 nm with a narrow size distribution. Attributed to high electrochemical active surface area (4.61 mF cm⁻²) and low interface resistance (2.35 Ω), CuO@PDA/CC electrode displays excellent electrochemical performance as a glucose sensor with high sensitivity of 1.843 μA cm⁻² mM⁻¹ in a wide linear range up to 4.985 mM and excellent stability. This work provides a facile approach to fabricating the flexible self-supported electrodes with well-controlled nanostructure and desirable interfacial properties for high-performance electrochemical sensors via regulating the transient cavitation intensity in the sonochemical process.