Recharge processes of paramagnetic centers during illumination in nitrogen-doped nanocrystalline titanium dioxide

Le, N. T.; Константинова, Е. А.; Кокорин, А. И.; Kodom, T.; Alonso-Vante, Nicolás

doi:10.1016/j.cplett.2015.06.062

Cited by 6 publications

(3 citation statements)

References 17 publications

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“…A disadvantage of bare TiO 2 is that it can absorb only UV light, i.e., the relatively small part of the solar spectrum because of its large band gap between 3 and 3.5 eV. Improving the light absorption of TiO 2 in the visible range is usually associated with its bulk doping or surface modification by incorporating some transition metal ions, , noble metals, , or nonmetal elements such as C, N, S, or F. − ,,, However, in many cases, the efficiency of such photocatalysts is rather low.…”

Section: Introductionmentioning

confidence: 99%

Determination of the Energy Levels of Paramagnetic Centers in the Band Gap of Nanostructured Oxide Semiconductors Using EPR Spectroscopy

et al. 2018

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A detailed analysis of the nature and photoinduced reactions of paramagnetic centers (PCs) in TiO 2 based semiconductor nanoparticles has been performed, and energy diagrams of the investigated samples with the energy level positions in the band gap are determined using electron paramagnetic resonance (EPR) technique under illumination in situ. This study gives a new method for constructing the zone diagram of nanostructured semiconductors. N • , Ti 3+ , and Mo 5+ PCs were detected in TiO 2 /MoO 3 samples, and Ti 3+ and V 4+ centers were observed in the TiO 2 /MoO 3 :V 2 O 5 one. The determined energy position of PCs in the band gap of nanostructured semiconductors are located from the valence band on 2.9 eV for Ti 3+ ions, 2.7 eV for Mo 5+ ions, 2.2 eV for V 4+ PCs, and 1.4 eV below the bottom of the conduction band for N • radicals. The effect of illumination is reversible during a long time: approximately 24 h because of a separation of the photogenerated charge carriers just after excitation between different semiconductor oxide nanosized particles connected by nanoheterojunctions. These results can be useful for understanding the mechanism of photocatalytic reactions and further practical applications of the nanoheterojunction materials such as TiO 2 /MoO 3 and TiO 2 /MoO 3 :V 2 O 5 oxides.

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Section: Introductionmentioning

confidence: 99%

Determination of the Energy Levels of Paramagnetic Centers in the Band Gap of Nanostructured Oxide Semiconductors Using EPR Spectroscopy

et al. 2018

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“…11 was reliably demonstrated in our previous papers. [19][20][21] The illumination (245-900 nm) of the samples did not lead to the appearance of any EPR signals. Yet, another reason existed for the absence of signals in the EPR spectrum.…”

Section: Resultsmentioning

confidence: 91%

Unveiling point defects in titania mesocrystals: a combined EPR and XPS study

et al. 2018

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“…This signal becomes stronger as t a increases, splitting in two peaks at 401.8 eV (NH 4 + remaining from the electrolyte) and 399 eV. This last emission peak is within the range of signals connected to interstitial N, (O–N • –Ti), and has been associated with electron transitions from Ti 3+ /oxygen vacancy centers to interstitial N atoms [35,37–39]. These substitutional N atoms can also be associated with the enhanced signal in the OH group band (531.5 eV) [40–41].…”

Section: Resultsmentioning

confidence: 99%

Impact of the anodization time on the photocatalytic activity of TiO₂ nanotubes

Díaz-Real¹,

Bandomo²,

Galindo‐de‐la‐Rosa³

et al. 2018

Beilstein J. Nanotechnol.

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Titanium oxide nanotubes (TNTs) were anodically grown in ethylene glycol electrolyte. The influence of the anodization time on their physicochemical and photoelectrochemical properties was evaluated. Concomitant with the anodization time, the NT length, fluorine content, and capacitance of the space charge region increased, affecting the opto-electronic properties (bandgap, bathochromic shift, band-edge position) and surface hydrophilicity of TiO2 NTs. These properties are at the origin of the photocatalytic activity (PCA), as proved with the photooxidation of methylene blue.

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Recharge processes of paramagnetic centers during illumination in nitrogen-doped nanocrystalline titanium dioxide

Cited by 6 publications

References 17 publications

Determination of the Energy Levels of Paramagnetic Centers in the Band Gap of Nanostructured Oxide Semiconductors Using EPR Spectroscopy

Determination of the Energy Levels of Paramagnetic Centers in the Band Gap of Nanostructured Oxide Semiconductors Using EPR Spectroscopy

Unveiling point defects in titania mesocrystals: a combined EPR and XPS study

Impact of the anodization time on the photocatalytic activity of TiO₂ nanotubes

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Recharge processes of paramagnetic centers during illumination in nitrogen-doped nanocrystalline titanium dioxide

Cited by 6 publications

References 17 publications

Determination of the Energy Levels of Paramagnetic Centers in the Band Gap of Nanostructured Oxide Semiconductors Using EPR Spectroscopy

Determination of the Energy Levels of Paramagnetic Centers in the Band Gap of Nanostructured Oxide Semiconductors Using EPR Spectroscopy

Unveiling point defects in titania mesocrystals: a combined EPR and XPS study

Impact of the anodization time on the photocatalytic activity of TiO2 nanotubes

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Impact of the anodization time on the photocatalytic activity of TiO₂ nanotubes