Scalable Fabrication of Stainless Steel–CuO Hybrid Nanostructured Electrodes for Nonenzymatic Glucose Sensing

A hybrid nanostructure electrode consisting of stainless-steel films decorated with copper oxide nanoparticles (CuONPs) was fabricated via direct current (DC) sputtering followed by thermal oxidation, and its structural, chemical, and electrochemical properties were systematically investigated. The nanoscale morphology and structure were examined by scanning electron microscopy (SEM) and transmission electron microscopy (TEM), including selected area electron diffraction (SAED), revealing well-defined copper nanostructures anchored to the stainless-steel surface. X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) confirmed the high crystallinity of the CuONPs and the coexistence of Cu+ and Cu2+ species (Cu2O, CuO, Cu(OH)2). Electrochemical studies in an alkaline medium demonstrated that the Cu+/Cu2+ active layer exhibits significant electrocatalytic activity toward glucose oxidation, producing a pronounced anodic response around 0.6 V vs carbon pseudoreference. The combination of crystalline CuONPs and a robust stainless-steel support, fabricated via a scalable process, makes this hybrid structure a promising candidate for nonenzymatic glucose detection.