Details
| Original language | English |
|---|---|
| Pages (from-to) | 51-57 |
| Number of pages | 7 |
| Journal | Journal of solid state chemistry |
| Volume | 187 |
| Early online date | 4 Jan 2012 |
| Publication status | Published - Mar 2012 |
Abstract
Solid-state processes of introducing oxygen vacancies and transference of fluorine to n-TiO 2 nanoparticles by co-milling with poly(tetrafluoroethylene) (PTFE) powder were examined by diffuse reflectance spectroscopy (DRS) of UV, visual, near- and mid-IR regions, thermal analyses (TG-DTA), energy-dispersive X-ray spectroscopy (EDXS), X-ray photoelectron spectroscopy (XPS), high-resolution transmission electron microscopy (HRTEM) and X-ray diffraction (XRD). The broad absorption peak at around 8800 cm -1 (1140 nm) was attributed to the change in the electronic states, viz. electrons trapped at the oxygen vacancies (Vo) and dd transitions of titanium ions. Incorporation of fluorine into n-TiO 2 was concentrated at the near surface region and amounted to ca. 40 at% of the total fluorine in PTFE, after co-milling for 3 h, as confirmed by the F1s XPS spectrum. The overall atomic ratio, F/Ti, determined by EDXS was 0.294. By combining these analytical results, a mechanism of the present solid state processes at the boundary between PTFE and n-TiO 2 was proposed. The entire process is triggered by the partial oxidative decomposition of PTFE. This is accompanied by the abstraction of oxygen atoms from the n-TiO 2 lattices. Loss of the oxygen atoms results in the formation of the diverse states of locally distorted coordination units of titania, i.e. TiO 6-nVo n, located at the near surface region. This leads subsequent partial ligand exchange between F and O, to incorporate fluorine preferentially to the near surface region of n-TiO 2 particles, where local non-crystalline states predominate.
Keywords
- Mechanochemical reaction, Oxidative decomposition, Oxygen vacancies, Poly(tetrafluoroethylene), Titania nanoparticles
ASJC Scopus subject areas
- Materials Science(all)
- Electronic, Optical and Magnetic Materials
- Materials Science(all)
- Ceramics and Composites
- Physics and Astronomy(all)
- Condensed Matter Physics
- Chemistry(all)
- Physical and Theoretical Chemistry
- Chemistry(all)
- Inorganic Chemistry
- Materials Science(all)
- Materials Chemistry
Cite this
- Standard
- Harvard
- Apa
- Vancouver
- BibTeX
- RIS
In: Journal of solid state chemistry, Vol. 187, 03.2012, p. 51-57.
Research output: Contribution to journal › Article › Research › peer review
}
TY - JOUR
T1 - Introduction of oxygen vacancies and fluorine into TiO 2 nanoparticles by co-milling with PTFE
AU - Senna, Mamoru
AU - Šepelák, Vladimir
AU - Shi, Jianmin
AU - Bauer, Benjamin
AU - Feldhoff, Armin
AU - Laporte, Vincent
AU - Becker, Klaus Dieter
N1 - Funding Information: M.S. thanks Alexander von Humboldt-Foundation to enable his research stay in Braunschweig. V.S. thanks the DFG (SPP1415) for supporting this work. V.L. acknowledges N. Xanthopoulos (EPFL–Interdisciplinary Centre for Electron Microscopy) for performing XPS analyses. The authors thank Prof. B. Malic for TG-DTA measurement, and Toho Titanium Co. Ltd. for the kind donation of anatase nanoparticles, TA50.
PY - 2012/3
Y1 - 2012/3
N2 - Solid-state processes of introducing oxygen vacancies and transference of fluorine to n-TiO 2 nanoparticles by co-milling with poly(tetrafluoroethylene) (PTFE) powder were examined by diffuse reflectance spectroscopy (DRS) of UV, visual, near- and mid-IR regions, thermal analyses (TG-DTA), energy-dispersive X-ray spectroscopy (EDXS), X-ray photoelectron spectroscopy (XPS), high-resolution transmission electron microscopy (HRTEM) and X-ray diffraction (XRD). The broad absorption peak at around 8800 cm -1 (1140 nm) was attributed to the change in the electronic states, viz. electrons trapped at the oxygen vacancies (Vo) and dd transitions of titanium ions. Incorporation of fluorine into n-TiO 2 was concentrated at the near surface region and amounted to ca. 40 at% of the total fluorine in PTFE, after co-milling for 3 h, as confirmed by the F1s XPS spectrum. The overall atomic ratio, F/Ti, determined by EDXS was 0.294. By combining these analytical results, a mechanism of the present solid state processes at the boundary between PTFE and n-TiO 2 was proposed. The entire process is triggered by the partial oxidative decomposition of PTFE. This is accompanied by the abstraction of oxygen atoms from the n-TiO 2 lattices. Loss of the oxygen atoms results in the formation of the diverse states of locally distorted coordination units of titania, i.e. TiO 6-nVo n, located at the near surface region. This leads subsequent partial ligand exchange between F and O, to incorporate fluorine preferentially to the near surface region of n-TiO 2 particles, where local non-crystalline states predominate.
AB - Solid-state processes of introducing oxygen vacancies and transference of fluorine to n-TiO 2 nanoparticles by co-milling with poly(tetrafluoroethylene) (PTFE) powder were examined by diffuse reflectance spectroscopy (DRS) of UV, visual, near- and mid-IR regions, thermal analyses (TG-DTA), energy-dispersive X-ray spectroscopy (EDXS), X-ray photoelectron spectroscopy (XPS), high-resolution transmission electron microscopy (HRTEM) and X-ray diffraction (XRD). The broad absorption peak at around 8800 cm -1 (1140 nm) was attributed to the change in the electronic states, viz. electrons trapped at the oxygen vacancies (Vo) and dd transitions of titanium ions. Incorporation of fluorine into n-TiO 2 was concentrated at the near surface region and amounted to ca. 40 at% of the total fluorine in PTFE, after co-milling for 3 h, as confirmed by the F1s XPS spectrum. The overall atomic ratio, F/Ti, determined by EDXS was 0.294. By combining these analytical results, a mechanism of the present solid state processes at the boundary between PTFE and n-TiO 2 was proposed. The entire process is triggered by the partial oxidative decomposition of PTFE. This is accompanied by the abstraction of oxygen atoms from the n-TiO 2 lattices. Loss of the oxygen atoms results in the formation of the diverse states of locally distorted coordination units of titania, i.e. TiO 6-nVo n, located at the near surface region. This leads subsequent partial ligand exchange between F and O, to incorporate fluorine preferentially to the near surface region of n-TiO 2 particles, where local non-crystalline states predominate.
KW - Mechanochemical reaction
KW - Oxidative decomposition
KW - Oxygen vacancies
KW - Poly(tetrafluoroethylene)
KW - Titania nanoparticles
UR - http://www.scopus.com/inward/record.url?scp=84857232406&partnerID=8YFLogxK
U2 - 10.1016/j.jssc.2011.12.036
DO - 10.1016/j.jssc.2011.12.036
M3 - Article
AN - SCOPUS:84857232406
VL - 187
SP - 51
EP - 57
JO - Journal of solid state chemistry
JF - Journal of solid state chemistry
SN - 0022-4596
ER -