Cu2O/MXene/rGO Ternary Nanocomposites as Sensing Electrodes for Nonenzymatic Glucose Sensors

Fine-tuning of the morphology from two-dimensional (2D)to three-dimensional(3D) nanostructures by structural engineering leads to improved biosensing.Herein, a 3D assembly of MXene and rGO nanosheets was synthesizedby a hydrothermal process, and then, a naturally abundant and promisingbiosensing catalyst of Cu2O was added by a coprecipitationmethod to prepare a 3D ternary composite (MXene graphene aerogel-Cu2O composite). The prepared ternary nanocomposite was characterizedby X-ray diffraction, field emission scanning electron microscopy(FE-SEM), Raman spectroscopy, and Brunauer-Emmett-Teller(BET). It exhibited a low crystallite size, spherical-shaped Cu2O, and a large surface area with a porous structure. Further,a sensing electrode was fabricated by the drop-casting method, andthen, a chronoamperometric (CA) study was performed to understandthe sensing performance of the 3D ternary composite. The fabricatedelectrode showed sensitivities of 264.52 and 137.95 & mu;A cm(-2) mM(-1) compared to 2D composites(126.6 & mu;A cm(-2) mM(-1)) withtwo wide linear ranges of 0.1-14 and 15-40 mM, respectively.The electrode also gave a low detection limit and good stability,selectivity, and reproducibility, thus making it suitable for thedetermination of glucose levels in human serum samples. These findingsreveal that the 3D network of MXene and rGO nanosheets assists ineffective charge transfer and promotes the sensing activity of nonenzymaticglucose sensors.