Highly Ordered TiO2-WO3 Modified Nanotubes Array for Photoelectrocatalytic Oxidation of Methyl Orange

Abstract

Coupled titanium dioxide-tungsten oxide array surface was used to remove methyl orange from water by photocatalytic anodic oxidation. The coating was prepared by anodizing a titanium foil in a glycerol/water electrolyte-containing NH₄F followed by thermal treatment. Moreover, subsequent WO₃ electrodeposition was realized on the previously obtained TiO₂ nanotubular structure. As comparison, TiO₂-WO₃ structures were obtained by adding a tungstate salt in the glycerol/water electrolyte during the anodization step of Ti foil. Scanning electron microscopy imaging showed that the array coating consisted of closely spaced nanotubes perpendicular to the titanium plate. Moreover, subsequent electrodeposition of WO₃ occurred on the wall of the nanotubes; when a tungstate salt was used during Ti anodization, the formation of nanotubes with different dimensions was observed.
The synthesized materials were studied for the photoelectrocatalytic oxidation of methyl orange under applied bias potential. The degradation efficiency obtained using TiO₂ nanotubes was higher than that obtained in presence of the coupled structure.