Raman investigation of nanosized TiO2

Abstract

Nanosizedwas prepared using the sol-gel procedure. The prepared powder was thermally treated up to TiO 2 1000 ÄC. X-ray di †raction (XRD) measurements showed that the starting powder and the samples obtained after heating this powder up to 500 ÄC were mixtures of anatase, as the dominant phase, and brookite. The crystallite sizes of the samples were estimated using the Scherrer equation. A new approach to the size determination of nanosized by low-wavenumber Raman scattering, was also applied. The particle sizes, determined by lowTiO 2 , wavenumber Raman scattering, were in agreement with the crystallite sizes measured by XRD. Rutile was produced by heat treatment of the starting powder at 850 ÄC and higher temperatures.

The application of Raman and anti-stokes Raman spectroscopy for in situ monitoring of structural changes in laser irradiated titanium dioxide materials

“…Raman spectra of the three crystalline phases of TiO 2 have been well reported [8][9][10][11][12][13][14].…”

“…These Raman bands are assigned to a mixture of anatase and rutile forms of the TiO 2 . Strong Raman bands at 144 (Eg), 398 (B1g), 515 (A1g , B1g), and 640 cm -1 (Eg) were observed along with a weak band at 197 cm -1 (Eg) which were assigned to the anatase form of TiO 2 in accordance with the literature [8][9][10][11][12][13][14]. This data is summarised in Table 1.…”

“…Raman spectroscopy is a very effective means of detecting these different crystalline phases in TiO 2 powders and the assignment of observed bands to rutile, anatase and brookite has been reported [8][9][10][11][12][13][14]. These crystalline phases are not thermodynamically stable as both anatase and brookite transform irreversibly and exothermically to rutile when heated to high temperatures [10,15,16].…”

The mechanochemical stability of hydrogen titanate nanostructures

“…1b). Such an upward shift of the anatase band at 144 cm -1 can be explained by a decrease in the size of the anatase particles [60][61][62] and the breaking of the TiO 2 stoichiometry [63][64][65]. During the milling process, the band of anatase at 632 cm -1 was overlapped with a rutile band appearing at 611 cm -1 , so the resulting band was shifted to the lower position.…”

Organized Silica Films Generated by Evaporation-Induced Self-Assembly as Hosts for Iron Oxide Nanoparticles

“…Raman microscopy may give useful information about the presence of nanoparticle species on the surface and in the pores of the films [37,38]. It also discriminates between different crystalline forms (e.g., hematite and maghemite, or magnetite in the case of iron oxides) [39,40,41,42] and sometimes even the size of the particles, through measured broadenings and shifts of the Raman bands [43]. Spectroscopic ellipsometry provides the thickness and the overall porosity of the films, and some indication of uniformity and orientation [44,45,46,47,48].…”