A novel self-cleaning, non-enzymatic glucose sensor working under a very low applied potential based on a Pt nanoparticle-decorated TiO2 nanotube array electrode

Abstract

In this paper, a non-enzymatic amperometric glucose sensor working under a very low applied potential of −0.5V (vs. saturated calomel electrode or SCE) was developed based on a Pt nanoparticle-decorated TiO2 nanotube array (Pt/TiO2 NTA) electrode. A highly ordered TiO2 NTA with a diameter of 200nm was fabricated by anodization of Ti in ethylene glycol containing 0.5wt% NH4F, 10vol% H2O, and 0.9vol% H2SO4. Pt nanoparticles ∼5nm in diameter were uniformly decorated inside the TiO2 nanotubes through ion-exchange reaction with Pt (NH3)4Cl2, followed by reduction with NaBH4. The morphology of the electrode was characterized by X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy, and transmission electron microscopy. The performance of the as-prepared electrode was characterized by cyclic voltammetry and chronoamperometry. The sensor can accurately detect glucose in 0.1M NaOH solution at an applied potential of −0.5V (vs. SCE) in the presence of interferences, such as ascorbic acid and uric acid, with a linear range of 1–15mM and a detection limit of 0.2mM at a signal-to-noise ratio of 3. The Pt/TiO2 synergistic effect shows a good self-cleaning ability. The electrocatalytic ability of the present Pt/TiO2 NTA electrode toward glucose oxidation under a very low applied potential has promising applications in blood glucose measurement and mediator-free anodes for glucose biofuel cells.