Facile Fabrication of a Nanocomposite Electrode for Enhanced Electrochemical Performance

A novel Nanocomposite electrode composed of zinc oxide (ZnO), copper oxide (CuO), reduced graphene oxide (rGO), and poly(acrylonitrile-co-acrylic acid) (PANINS), denoted as ZnO/CuO/rGO/PANINS, was synthesized via a one-step in situ polymerization strategy for non-enzymatic glucose detection. The PANINS polymer was uniformly coated onto the ZnO/CuO/rGO framework, enhancing the structural integrity and conductivity of the resulting electrode. Structural and physicochemical characterizations were conducted using UV-visible spectroscopy, Fourier-transform infrared spectroscopy (FTIR), and X-ray diffraction (XRD) to evaluate the optical properties, functional groups, and crystallinity of the synthesized Nanocomposite. Electrochemical performance was assessed using cyclic voltammetry (CV) and amperometry in 0.1 M NaOH electrolyte. The modified glassy carbon electrode (GCE) exhibited significantly enhanced current responses compared to unmodified and non-PANINS-modified counterparts, attributed to the synergistic catalytic activity of the Nanocomposite components. The active surface area increased from 0.001 cm² (bare GCE) to 0.199 cm² (ZnO/CuO/rGO/PANINS-modified GCE). The sensor demonstrated a lower onset potential and higher peak current for glucose oxidation, indicating improved electro catalytic activity. Amperometric analysis revealed a linear detection range of 2-10 mM glucose, with a high sensitivity of 5660 μA mM ^- ¹ cm ^- ², a low detection limit of 0.00054 μM, and a rapid response time of 3 seconds. The sensor also exhibited excellent selectivity toward glucose in the presence of common interfering species, along with good reproducibility (RSD = 2.89 %), repeatability (RSD = 4.2 %), and long-term stability, retaining 89.5 % of its initial current response after 10 days. The sensor’s applicability was validated in real blood samples, showing strong correlation with standard spectrophotometric methods. These results suggest that the ZnO/CuO/rGO/PANINS Nanocomposite is a promising platform for the development of high-performance, non-enzymatic electrochemical glucose sensors.