Study of surface fluorination of photocatalytic TiO{sub 2} by thermal shock method

Journal Article · Thu Mar 15 04:00:00 EDT 2012 · Journal of Solid State Chemistry

DOI:https://doi.org/10.1016/J.JSSC.2012.01.034· OSTI ID:22012077

Le, Tien Khoa ^[1]; Flahaut, Delphine ^[1]; Foix, Dominique; Blanc, Sylvie ^[1]; Hung Nguyen, Huu Khanh; Xuan Huynh, Thi Kieu ^[2]; Martinez, Herve ^[1]

---

1. IPREM/ECP (UMR 5254), University of Pau, Helioparc, 2 av. Pierre Angot, 64053 Pau cedex 9 (France)
2. University of Science - Ho Chi Minh city, 227 Nguyen Van Cu Street, Ho Chi Minh City (Viet Nam)

Surface fluorinated TiO{sub 2} powders were prepared by thermal shock method and an overall comparative study was achieved on the basis of XRD, SEM, UV-vis and XPS analyses. The main objective was to elucidate the influences of surface fluorination on the crystallite structures, morphologies, optical properties and surface chemistry with the temperature. According to the results, the surface fluorination under thermal shock method below 600 Degree-Sign C did not change the crystallite structure and the particles size, but successfully created chemisorbed fluoride ions, oxygen vacancies and increased the hydroxyl groups on the surface of TiO{sub 2}. The presence of oxygen vacancies was assigned to the red shift of TiO{sub 2} optical absorption edge, which was the origin of visible-light-induced photocatalytic activity of these samples. For the thermal shock temperatures over 600 Degree-Sign C, the K{sub 2}Ti{sub 6}O{sub 13}-like phase was formed, resulting from the decrease of surface hydroxyl groups and the blue shift in absorption edge which reduced the photocatalytic activity. - Graphical abstract: The influence of fluorination on the surface of TiO{sub 2} by thermal shock method at several temperatures has been investigated by following the evolution of the F1s spectra obtained by X-ray photoelectron spectroscopy. The blank peaks are assigned to the chemisorbed fluoride ions on the samples surface and the filled peaks to fluorine atoms in oxygenated environment of solid solution TiO{sub 2-x}F{sub x}, which is originated from the substitution of F ions for O ions in the TiO{sub 2} lattice. Highlights: Black-Right-Pointing-Pointer Surface fluorination of TiO{sub 2} P25 by thermal shock method. Black-Right-Pointing-Pointer Structure, morphology, surface and photocatalytic properties of fluorinated TiO{sub 2}. Black-Right-Pointing-Pointer Low thermal shock temperatures increase the photocatalytic activity. Black-Right-Pointing-Pointer Fluoride ions chemisorbed on the surface without structure and morphology change. Black-Right-Pointing-Pointer Formation of K{sub 2}Ti{sub 6}O{sub 13} phase at high thermal shock temperatures.

• OSTI ID: 22012077
• Journal Information: Journal of Solid State Chemistry, Journal Name: Journal of Solid State Chemistry Vol. . 187; ISSN 0022-4596; ISSN JSSCBI
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
FLUORIDES
FLUORINATION
MORPHOLOGY
OPTICAL PROPERTIES
OXYGEN
PARTICLE SIZE
PEAKS
PHOTOCATALYSIS
POWDERS
SCANNING ELECTRON MICROSCOPY
SOLID SOLUTIONS
SPECTRA
SURFACES
THERMAL SHOCK
TITANIUM OXIDES
X-RAY DIFFRACTION
X-RAY PHOTOELECTRON SPECTROSCOPY