TiO2 nanotubes modified with cadmium oxide for photoelectrocatalytic oxidation of alcohols

Abstract

TiO2 nanotube (TNT) electrodes were fabricated by electrochemical anodization of titanium in ethylene glycol electrolyte with added NH4F (0.5 wt.%) and water (2 % w/w). The (TNT)-cadmium oxide (CdO) composite was fabricated using potentiostatic cathodic deposition. Structural properties of the obtained coatings have been investigated by scanning electron microscopy and X-Ray photoelectron spectroscopy, Raman spectroscopy, X-Ray diffraction and transmission electron microscopy. The TNT-CdO electrode demonstrates high efficiency in photoelectrochemical degradation of methanol, ethylene glycol, glycerol and sorbitol in aqueous solutions of 0.1 M Na2SO4 upon irradiation by a simulated sunlight. The highest photooxidation currents were obtained for sorbitol. Intensity-modulated photocurrent spectroscopy shows that the photoelectrocatalysis efficiency is due to suppression of the electron-hole pairs’ recombination and to increase in the rate of photo-induced charge transfer. Thus, the TNT-CdO composite is an effective photoanode for developing the technology of photoelectrochemical degradation of sorbitol and other alcohols by-products of biofuel production.