Ti/TiO2 nanotube array electrode as a new sensor to photoelectrocatalytic determination of ethylene glycol

Abstract

The photoelectrocatalytic oxidation behaviour of ethylene glycol (EG) was studied in the present work using the TiO2-modified Ti foil (Ti/TiO2) electrode. The Ti/TiO2 nanotube array (Ti-NTA) electrode was prepared by anodizing of the Ti foil in the HF aqueous solution (0.2% v/v). The anodization was conducted in the constant 30 V for 2 h, and then the as-prepared Ti-NTA electrode was calcinated at 50 ∘C for 2 h. The surface morphology of Ti- NTA electrode was studied using scanning electron microscopy images. For EG determination, the photocurrent of EG (EG oxidation current in the UV irradiation) was assessed using the hydrodynamic photoamperometric method in the phosphate buffers. Ultimately, the optimum conditions of EG determination were studied in various pH values and applied bias potentials, and the pH = 3.0 and E= 1.0 V (vs. reference electrode) were determined as the optimum conditions. It was found that the photocurrent of EG was linearly dependent on the concentration of EG in the range of 3.0 × 10 −5 to 0.88 mol l −1, and the detection limit of EG determination was found to be 7.2 × 10−6 mol l−1 (3 σ).