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

Elizaveta Konstantinova; Timofey Savchuk; Olga Pinchuk; Ekaterina Kytina; Elizaveta Ivanova; Lidiya Volkova; Vladimir Zaitsev; Alexander Pavlikov; Elena Elizarova

doi:10.3390/molecules27228080

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

Molecules. 2022 Nov 21;27(22):8080. doi: 10.3390/molecules27228080.

Authors

Elizaveta Konstantinova^{1

2

3}, Timofey Savchuk^{1

4

5}, Olga Pinchuk⁴, Ekaterina Kytina¹, Elizaveta Ivanova⁶, Lidiya Volkova⁷, Vladimir Zaitsev¹, Alexander Pavlikov¹, Elena Elizarova⁸

Affiliations

¹ Physics Department, M.V. Lomonosov Moscow State University, Moscow 119991, Russia.
² Institute of Nano-, Bio-, Information, Cognitive and Socio-Humanistic Sciences and Technologies, Moscow Institute of Physics and Technology (National Research University), Moscow 141701, Russia.
³ A.M. Prokhorov General Physics Institute of RAS, Moscow 119991, Russia.
⁴ Institute of Advanced Materials and Technologies, National Research University of Electronic Technology-MIET, Moscow 124498, Russia.
⁵ Institute of General and Ecological Chemistry, Lodz University of Technology, 90-924 Lodz, Poland.
⁶ Phystech School of Electronics, Photonics and Molecular Physics, Moscow Institute of Physics and Technology (National Research University), Moscow 141701, Russia.
⁷ Department of Structural Analysis and Metrology, Institute of Nanotechnology of Microelectronics of the Russian Academy of Sciences, Moscow 119991, Russia.
⁸ Department of Food Hygiene and Toxycology, Institute of Vocational Education, I.M. Sechenov First Moscow State Medical University (Sechenov University), Moscow 119435, Russia.

Abstract

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 TiO₂ nanotubes/Cu_xO 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 TiO₂ 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 Cu₂O, while in air treated ones there is only CuO. In the TiO₂ nanotubes/Cu_xO samples, Cu²⁺ ions and molecular O₂^- radicals were detected while in TiO₂ nanotubes only carbon dangling bond defects are present. The dynamics of O₂^- radicals under illumination are discussed. It was shown that the TiO₂ nanotubes do not exhibit photocatalytic activity under visible light. The mechanism of the photocatalytic reaction on the surface of the TiO₂ nanotubes/Cu_xO 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 O₂^- radicals. The results obtained are completely original and indicate the high promise of the prepared photocatalysts.

Keywords: TiO2 nanotubes/CuxO; copper ions; molecular oxygen anion radicals; nanoheterostructures; organic molecules photodegradation; photocatalytic activity.

Abstract

Grants and funding