Recyclable Non-Enzymatic Glucose Sensor Based on Ni/NiTiO₃ /TiO₂ Nanotube Arrays

A non-enzymatic amperometric glucose sensor that can be renewed by light irradiation is described. It is composed of Ni/NiTiO₃ /TiO₂ nanotube arrays (NTAs) prepared by a simple hydrothermal treatment of as-anodized TiO₂ NTAs in a nickel acetate solution followed by annealing under H₂ /Ar. The Ni/NiTiO₃ /TiO₂ NTAs exhibit excellent electrocatalytic activity towards glucose oxidation in a 1.0 M NaOH supporting solution at a low applied potential of 0.4 V (vs. Ag/AgCl) with a high sensitivity of 456.4 μA cm^-2  mM^-1 and a low detection limit of 0.7 μM (S/N=3). The excellent electrochemical biosensing properties for glucose detection can be attributed to the orderly vertical alignment, large accessible surface, high conductivity, and electroactive Ni^II /Ni^III redox couple. Meanwhile, owing to their high photocatalytic activity, Ni/NiTiO₃ /TiO₂ NTAs can readily decompose the organic fouling species generated on the electrode surface during glucose detection under light irradiation so that the original sensitivity and selectivity can be restored. The Ni/NiTiO₃ /TiO₂ NTAs electrode provides a promising renewable platform enabling long-term glucose monitoring with high sensitivity and selectivity.