Spectral dependence of UV light penetration into powder TiO2 anatase

Ruslan V. Mikhaylov*, Polina E. Lavrik, Vyacheslav N. Kuznetsov, Nadezhda I. Glazkova

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

3 Scopus citations

Abstract

The penetration depth of UV monochromatic light into deposited TiO2 anatase powder was investigated. The light penetration depth was considered in units of numbers of surface hole, Ns, and electron, NO2, centers activated during irradiation. The numbers of hole centers Ns were obtained from photostimulated oxygen isotope exchange reaction registered by means of mass spectrometry. The numbers of electron centers NO2 were obtained from subsequent thermo-programmed desorption spectroscopy of photoadsorbed oxygen O2-. It was shown that the depth D of UV light penetration into UV absorbing TiO2 powder coat depends on the wavelength and intensity I0 of incident UV light and obeys to the equation DI0=[Formula presented]lg(I0/Im) obtained from the Beer–Lambert–Bouguer law with effective extinction coefficient keff and minimal value of light intensity Im, below which the photoactivation is considered negligible. Commonly, the value Im has an order of a few microwatts/cm2 for activation of electron and hole type centers except for a case of 334 nm falling into the band of the first direct band-to-band transition of anatase, where relatively high threshold value Im=0.063 mW/cm2 for photoactivation of hole centers was revealed. Effective extinction coefficient keff may be considered proportional to the absorption coefficient of TiO2 in the region of fundamental absorption, whereas, in the non-fundamental absorption region, keff exceeds significantly that of TiO2 due to, probably, dominating scattering processes. At small intensities of the incident light, there is a strong sensitivity of the penetration depth (and activated surface) to the intensity.

Original languageEnglish (US)
Article number113954
JournalJournal of Photochemistry and Photobiology A: Chemistry
Volume430
DOIs
StatePublished - Sep 1 2022

Bibliographical note

Funding Information:
The reported study was funded by RFBR according to the research project ? 19-02-00749. Authors are grateful to Saint-Petersburg State University (PureID 73032813) and to the Resource Centers ?Nanophotonics?, ?Centre for X-ray diffraction Studies?, ?Centre for Innovative Technologies of Composite Nanomaterials? and ?Nanotechnology? of Saint-Petersburg State University for the sample characterization by means of DRS, XRD, BET, and TEM measurements.

Funding Information:
The reported study was funded by RFBR according to the research project № 19-02-00749. Authors are grateful to Saint-Petersburg State University (PureID 73032813) and to the Resource Centers “Nanophotonics”, “Centre for X-ray diffraction Studies”, “Centre for Innovative Technologies of Composite Nanomaterials” and “Nanotechnology” of Saint-Petersburg State University for the sample characterization by means of DRS, XRD, BET, and TEM measurements.

Publisher Copyright:
© 2022 Elsevier B.V.

Keywords

  • Hombifine N
  • Light penetration depth
  • Oxygen isotope exchange
  • Titanium dioxide
  • TPD of oxygen

ASJC Scopus subject areas

  • General Chemistry
  • General Chemical Engineering
  • General Physics and Astronomy

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