Synthesis of pure ZnO and carbon nanoparticle/ZnO nanostructures for highly efficient glucose sensors

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ABSTRACT This work presents a promising method to prepare pure zinc oxide (ZnO) films and carbon nanoparticles (CNPs) decorated ZnO (CNP/ZnO) nanostructured films as glucose sensors. ZnO nanostructure film was grown on Zn foil via the anodisation method, whereas the carbon nanoparticles were synthesised by the hydrothermal method, the decoration process of carbon nanoparticles on ZnO film nanocomposites was conducted using the ultrasonication method. Numerous experiments were conducted, such as microstructure observation, crystallinity analysis, and electrochemical property research. The nanostructures were ascertained by energy-dispersive X-ray spectroscopy (EDX), field-emission scanning electron microscopy (FE-SEM), transmission electron microscope (TEM), UV-vis spectroscopy, photoluminescence (PL) measurements, and X-ray diffraction (XRD). ZnO NPs displayed a structure with an average crystallite size of 5.12–13.47 nm, and the PL emission spectra were found to be in the 387 nm range, ZnO films were created by annealing ZnO samples at 200°C for 2 h, and FE-SEM presented nanoparticle-like shapes with a particle size range of (20–50 nm) for voltage anodisation (6 v). This led to an elevation of the energy gap to 3.20 eV. The electrochemical characterisation of the CNPs/ZnO nanostructures refines remarkably the sensitivity to glucose via pure zinc oxide nanostructures. The CNP/ZnO nanostructures demonstrated improved glucose-sensing ability with a sensitivity value of 2827 µA. m M − 1 . The low detection limit is 0.8 mm with a linear range from (0.3 mm to 1 mm). The sensitivity and repeatability of the biosensors were assessed by measuring and analysing their I–V characteristics at different glucose concentrations. Based on a straightforward, affordable, and innovative sensor design, this result validates the sensor’s significant potential as a high-performance nonenzymatic glucose sensor. It was observed that when zinc oxide films were decorated with carbon nanoparticles, there was an increase in the sensitivity of glucose detection. This is due to an increase in charge transfer and conductivity, as well as an increase in the oxidation and reduction process.