High-performance non-enzymatic glucose sensor based on nickel-microcrystalline graphite-boron doped diamond complex electrode

Abstract

A nickel-microcrystalline graphite-boron doped diamond (Ni-MG-BDD) complex electrode was fabricated by thermal catalytic etching BDD film with Ni layer. Scanning electron microscopy, energy dispersive X-ray spectrum and Raman spectroscopy were utilized to characterize the morphology, composition of the complex electrode, respectively. Nickel particles with different sizes are demonstrated to sink into the crystal facet and grain boundary of the BDD film, which not only increases the specific surface area and the electrochemical stability of the electrode, but also catalyzes sp3-bonded diamond into sp2-bonded microcrystalline graphitic carbon in the cooling process. The presence of microcrystalline graphite mixed with diamond film is confirmed to increase the conductivity of the electrode. Electrochemical results indicate that the Ni-MG-BDD complex electrode shows excellent electrochemical performance for glucose oxidation. The proposed electrode shows wide linear ranges for glucose concentrations of 0.002–0.5 and 0.5–15.5mM with high sensitivities of 1010.8 and 660.8μAmM−1cm−2, respectively. In addition, the electrode exhibits a low detection limit of 0.24μM (S/N=3), good selectivity and reproducibility, and excellent stability during the long-term electrochemical detection.