Abstract

The solid-gas phase photo-catalytic activities of rutile TiO2 and TiOn (1<n<2) sub-oxide phases have been evaluated. Varying concentrations of Ti3+ defects were introduced into the rutile polymorph of titanium dioxide through carbo-thermal reduction at temperatures ranging from 350°C to 1300°C. The resulting sub-oxides formed were characterized by X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy, impedance spectroscopy and UV-visible diffuse reflectance spectroscopy. The presence of Ti3+ in rutile exposed to high reduction temperatures was confirmed by X-ray diffraction. In addition, a Ti3+-Ti4+ system was demonstrated to enhance the photo-catalytic properties of rutile for the degradation of the air pollutants NO2 and CO2 under UV irradiation of wavelengths (λ) 376-387nm and 381-392 nm. The optimum reduction temperature for photo-catalytic activity was within the range 350-400 ºC and attributed to improved charge-separation. The materials that were subject to carbo-thermal reduction at temperatures of 350°C and 400°C exhibited electrical conductivities over one hundred times higher compared to the non-reduced rutile. The results highlight that sub-oxide phases form an important alternative approach to doping with other elements to improve the photo-catalytic performance of TiO2. Such materials are important for applications such as self-cleaning where particles can be incorporated into surface coatings.
LanguageEnglish
Number of pages15
JournalMaterials
Early online date7 Jan 2019
StatusE-pub ahead of print - 7 Jan 2019

Keywords

  • Photocatalysis
  • TiO2
  • sub-oxide

Cite this

Solid-gas phase photo-catalytic behaviour of rutile and TiOn (1<n<2) sub-oxide phases for self-cleaning applications. / Nuño, Manuel; Adamaki, Vaia; Tobaldi, D.M.; Hortigüela Gallo , Maria; Otero-Irurueta, Gonzalo ; Bowen, Christopher; Ball, Richard.

In: Materials, 07.01.2019.

Research output: Contribution to journalArticle

Nuño M, Adamaki V, Tobaldi DM, Hortigüela Gallo M, Otero-Irurueta G, Bowen C et al. Solid-gas phase photo-catalytic behaviour of rutile and TiOn (1<n<2) sub-oxide phases for self-cleaning applications. Materials. 2019 Jan 7.
Nuño, Manuel ; Adamaki, Vaia ; Tobaldi, D.M. ; Hortigüela Gallo , Maria ; Otero-Irurueta, Gonzalo ; Bowen, Christopher ; Ball, Richard. / Solid-gas phase photo-catalytic behaviour of rutile and TiOn (1<n<2) sub-oxide phases for self-cleaning applications. In: Materials. 2019.
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abstract = "The solid-gas phase photo-catalytic activities of rutile TiO2 and TiOn (1<n<2) sub-oxide phases have been evaluated. Varying concentrations of Ti3+ defects were introduced into the rutile polymorph of titanium dioxide through carbo-thermal reduction at temperatures ranging from 350°C to 1300°C. The resulting sub-oxides formed were characterized by X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy, impedance spectroscopy and UV-visible diffuse reflectance spectroscopy. The presence of Ti3+ in rutile exposed to high reduction temperatures was confirmed by X-ray diffraction. In addition, a Ti3+-Ti4+ system was demonstrated to enhance the photo-catalytic properties of rutile for the degradation of the air pollutants NO2 and CO2 under UV irradiation of wavelengths (λ) 376-387nm and 381-392 nm. The optimum reduction temperature for photo-catalytic activity was within the range 350-400 ºC and attributed to improved charge-separation. The materials that were subject to carbo-thermal reduction at temperatures of 350°C and 400°C exhibited electrical conductivities over one hundred times higher compared to the non-reduced rutile. The results highlight that sub-oxide phases form an important alternative approach to doping with other elements to improve the photo-catalytic performance of TiO2. Such materials are important for applications such as self-cleaning where particles can be incorporated into surface coatings.",
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AU - Otero-Irurueta, Gonzalo

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AB - The solid-gas phase photo-catalytic activities of rutile TiO2 and TiOn (1<n<2) sub-oxide phases have been evaluated. Varying concentrations of Ti3+ defects were introduced into the rutile polymorph of titanium dioxide through carbo-thermal reduction at temperatures ranging from 350°C to 1300°C. The resulting sub-oxides formed were characterized by X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy, impedance spectroscopy and UV-visible diffuse reflectance spectroscopy. The presence of Ti3+ in rutile exposed to high reduction temperatures was confirmed by X-ray diffraction. In addition, a Ti3+-Ti4+ system was demonstrated to enhance the photo-catalytic properties of rutile for the degradation of the air pollutants NO2 and CO2 under UV irradiation of wavelengths (λ) 376-387nm and 381-392 nm. The optimum reduction temperature for photo-catalytic activity was within the range 350-400 ºC and attributed to improved charge-separation. The materials that were subject to carbo-thermal reduction at temperatures of 350°C and 400°C exhibited electrical conductivities over one hundred times higher compared to the non-reduced rutile. The results highlight that sub-oxide phases form an important alternative approach to doping with other elements to improve the photo-catalytic performance of TiO2. Such materials are important for applications such as self-cleaning where particles can be incorporated into surface coatings.

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