Novel graphenic-SiC nanotubes (g-SiCNT) and Cu-doped g-SiCNT/CuO composite as the effective nonenzymatic glucose sensors

Abstract

In this work, we present a novel synthesis of graphenic SiC nanotube (g-SiCNT), its Cu-doped structure (Cu/g-SiCNT), and Cu/g-SiCNT/CuO nanocomposite as the effective electrodes for glucose oxidation. The structures of the synthesized compounds were characterized by FT-IR, Raman, XRD, XPS, SEM/EDX, and TEM. The Cu/g-SiCNT/ electrode has shown a better response in glucose oxidation than CuO nanoparticles and CNT/CuO electrodes. Cu/g-SiCNT/CuO nanocomposite shows the linear response in 1–4480 µM glucose concentration and excellent electrochemical glucose sensing with sensitivity and detection limit of 2051 µA/cm2 mM and 0.8 μM, respectively. The synthesized sensor was shown good selectivity, reproducibility, and stability towards glucose, and was also successfully applied in the determination of glucose in real blood plasma samples. The enhancement of electrochemical activities can justify these results by synergetic effects of Cu/g-SiCNT as the conductive substrate and CuO as the active electrochemical in the Cu/g-SiCNT/CuO composite. The high electrical conductivity of g-SiCNT is related to its many active sites which are caused by the presence of Si and Cu dopants in the nanotube graphenic structure of g-SiCNT. These electrochemically active sites can adsorb and activate the analytes and accelerate the charge transfer, enhancing the electrochemical sensing properties.