Photocatalytic oxidation of benzyl alcohol and the photoelectrochemical water splitting of visible light-activated TiO2 nanostructures prepared by one-step titanium anodization

Photocatalytic oxidation of benzyl alcohol and the photoelectrochemical water splitting of visible light-activated TiO2 nanostructures prepared by one-step titanium anodization

Mohamad Mohsen Momeni, Mohammad Taghinejad, Yousef Ghayeb, Alireza Najafi Chermahini, Robabeh Bagheri, Zhenlun Song

Doped TiO₂ nanostructures have been prepared by one-step anodization of titanium in an ethylene glycol-based electrolyte with different concentrations of potassium hexacyanocobaltate and their catalytic activity in photocatalytic oxidation of benzyl alcohol to benzaldehyde, and photoelectrochemical water splitting under visible light has been investigated in this work. Field emission scanning electron microscopy, X-ray photoelectron spectroscopy, Raman spectroscopy, X-ray diffraction, energy-dispersive X-ray spectroscopy and UV–visible techniques have been used to determine the effect of the concentration of the doping agent on the morphology, structure and optical properties of doped TiO₂ thin films. Doped TiO₂ nanostructures show significant morphological differences in comparison with commercial bare TiO₂ nanotube samples, based on SEM analysis. Different electrochemical methods have been used to study the effect of the concentration of the doping agents on the photoelectrocatalytic activity of the samples. The as-anodized doped TiO₂ electrodes were observed to show higher photocatalytic activity compared with the bare TiO₂ due to the high absorption of visible light and reduction in the recombination of photogenerated charges. Very high surface area, good photocatalytic performance, moderate conversion (about 42%) and high selectivity ( > 99%) for oxidation of benzyl alcohol to benzaldehyde at ambient temperature under visible light illumination in acetonitrile solvent were shown by the doped TiO₂ nanoporous sample anodized in electrolyte containing 0.015 M potassium hexacyanocobaltate (sample CT15). Finally, the photoelectrochemical water splitting efficiency of the samples prepared has also been investigated.

Applied Physics A