Photoelectron Properties and Organic Molecules Photodegradation Activity of Titania Nanotubes with CuO Nanoparticles Heat Treated in Air and Argon.

Titania is very famous photocatalyst for decomposition of organic pollutants. Its photocatalytic properties significantly depend on the morphology and chemical composition of the samples. Herein, the TiO nanotubes/CuO nanoheterostructures have been synthesized and the effect of heat treatment performed in molecular atmospheres of air and argon on their photoelectrochemical and photocatalytic properties has been studied. The prepared samples have a higher reaction rate constant compared to TiO nanotubes in the decomposition reaction of methylene blue molecules. It is established that in argon treated nanoheterostructures, the copper oxide is present in two phases, CuO and CuO, while in air treated ones there is only CuO. In the TiO nanotubes/CuO samples, Cu ions and molecular O radicals were detected while in TiO nanotubes only carbon dangling bond defects are present. The dynamics of O radicals under illumination are discussed. It was shown that the TiO nanotubes do not exhibit photocatalytic activity under visible light. The mechanism of the photocatalytic reaction on the surface of the TiO nanotubes/CuO samples was proposed. It is assumed that a photocatalytic decomposition of organic molecules under visible light at the surface of the nanoheterostructures under investigation is realized mainly by the reaction of these molecules with photogenerated O radicals. The results obtained are completely original and indicate the high promise of the prepared photocatalysts.