Mechanism of hydrogen modification of titanium-dioxide
Author(s)
Rahimi, Nazanin
Pax, Randolph A
Gray, Evan MacA
Griffith University Author(s)
Year published
2020
Metadata
Show full item recordAbstract
Recent explanations of the enhancement of the electrical properties of hydrogen-modified anatase-TiO2 propose mid-band gap states just below the conduction band and relate these to the creation of a disordered surface layer on an unmodified crystalline core. In this paper, the focus is on hydrogen modification of rutile-TiO2, which also acquires enhanced electrical properties. Oxygen-deficient TiO2–x was produced by exposing rutile to hydrogen at temperatures up to 730 °C. The desorption of hydrogen was studied by mass spectrometry measurements at temperatures up to 730 °C. All the evidence gathered in this new study is ...
View more >Recent explanations of the enhancement of the electrical properties of hydrogen-modified anatase-TiO2 propose mid-band gap states just below the conduction band and relate these to the creation of a disordered surface layer on an unmodified crystalline core. In this paper, the focus is on hydrogen modification of rutile-TiO2, which also acquires enhanced electrical properties. Oxygen-deficient TiO2–x was produced by exposing rutile to hydrogen at temperatures up to 730 °C. The desorption of hydrogen was studied by mass spectrometry measurements at temperatures up to 730 °C. All the evidence gathered in this new study is consistent with the absorption of hydrogen into the interior of the rutile particle. Re-examination of published x-ray diffraction results does not reveal evidence for a disordered surface layer on hydrogen-modified rutile. It therefore appears that the explanation of enhanced electrical properties owing to surface-only processes is incomplete, especially for rutile, but probably for anatase as well.
View less >
View more >Recent explanations of the enhancement of the electrical properties of hydrogen-modified anatase-TiO2 propose mid-band gap states just below the conduction band and relate these to the creation of a disordered surface layer on an unmodified crystalline core. In this paper, the focus is on hydrogen modification of rutile-TiO2, which also acquires enhanced electrical properties. Oxygen-deficient TiO2–x was produced by exposing rutile to hydrogen at temperatures up to 730 °C. The desorption of hydrogen was studied by mass spectrometry measurements at temperatures up to 730 °C. All the evidence gathered in this new study is consistent with the absorption of hydrogen into the interior of the rutile particle. Re-examination of published x-ray diffraction results does not reveal evidence for a disordered surface layer on hydrogen-modified rutile. It therefore appears that the explanation of enhanced electrical properties owing to surface-only processes is incomplete, especially for rutile, but probably for anatase as well.
View less >
Journal Title
Journal of Alloys and Compounds
Volume
815
Subject
Condensed matter physics
Materials engineering
Resources engineering and extractive metallurgy
Science & Technology
Physical Sciences
Chemistry, Physical
Materials Science, Multidisciplinary