Cu₂O/MXene/rGO\nTernary Nanocomposites as\nSensing Electrodes for Nonenzymatic Glucose Sensors

Abstract

Fine-tuning of the morphology from two-dimensional (2D)\nto three-dimensional\n(3D) nanostructures by structural engineering leads to improved biosensing.\nHerein, a 3D assembly of MXene and rGO nanosheets was synthesized\nby a hydrothermal process, and then, a naturally abundant and promising\nbiosensing catalyst of Cu₂O was added by a coprecipitation\nmethod to prepare a 3D ternary composite (MXene graphene aerogel–Cu₂O composite). The prepared ternary nanocomposite was characterized\nby X-ray diffraction, field emission scanning electron microscopy\n(FE-SEM), Raman spectroscopy, and Brunauer–Emmett–Teller\n(BET). It exhibited a low crystallite size, spherical-shaped Cu₂O, and a large surface area with a porous structure. Further,\na sensing electrode was fabricated by the drop-casting method, and\nthen, a chronoamperometric (CA) study was performed to understand\nthe sensing performance of the 3D ternary composite. The fabricated\nelectrode showed sensitivities of 264.52 and 137.95 μA cm^–2 mM^–1 compared to 2D composites\n(126.6 μA cm^–2 mM^–1) with\ntwo wide linear ranges of 0.1–14 and 15–40 mM, respectively.\nThe electrode also gave a low detection limit and good stability,\nselectivity, and reproducibility, thus making it suitable for the\ndetermination of glucose levels in human serum samples. These findings\nreveal that the 3D network of MXene and rGO nanosheets assists in\neffective charge transfer and promotes the sensing activity of nonenzymatic\nglucose sensors.