Raman scattering by nanophase titanium dioxide

Laser-flash-photolysis-spectroscopy: a nondestructive method?

“…Probably, such alteration happened due to an increase in particle size, 20 while the inuence of the B 1g mode of the rutile phase with a maximum at 143 cm À1 could be excluded for this interpretation because of its low line intensity. [21][22][23] However, the detected anatase to rutile phase transition does not explain the dark grey-blue coloration of the UV100 TiO 2 powder aer the exposure to the laser. Fig.…”

“…When the analyzing beam is focused on a white area, the Raman spectrum shows only anatase peaks: 149, 200, 395.5, 513 and 636.5 cm À1 , which can be assigned to major modes of the anatase phase as E g , E g , B 1g , and superpositions of A 1g and B 1g , and E g , respectively. [20][21][22][23] The Raman spectrum of the dark areas exhibits additional peaks with maxima at 238, 447.5 and 610 cm À1 . These three bands can be attributed to the two-phonon scattering, E g , and A 1g modes, of the rutile phase, respectively.…”

“…These three bands can be attributed to the two-phonon scattering, E g , and A 1g modes, of the rutile phase, respectively. [21][22][23][24] Moreover, the highest anatase peak at 149 cm À1 Fig. 1 (a) Micrograph of an illuminated UV100 sample surface (50Â magnification).…”

Unravelling water effects on solid acid catalysts: Case study of TiO 2 /SiO 2 as a catalyst for the dehydration of isobutanol

“…For SiO 2 -A support, a weak broad band around 25.2° was observed and indexed as the (101) plane of anatase TiO 2 [30,31]. Raman spectra of these compounds ( Figure S1 in the Supporting Information) which contained bands around 151, 202 (shoulder), 401, 493, 510 and 640 cm -1 clearly evidenced the presence of anatase nanocrystallites in these samples [32,33]. The very broad features around 460 and 810 cm -1 corresponded respectively to δ(Si-O-Si) and ν(Si-O-Si) of SiO 2 support whereas the remaining band at 607 cm -1 was attributed to D2 defects (3membered rings) [34].…”

Synthesis, isolation, and redispersion of resorcinarene-capped anatase TiO2 nanoparticles in nonaqueous solvents

“…The anatase TiO 2 , which is one of the three different crystalline polymorphs of TiO 2 : rutile (tetragonal), anatase (tetragonal), and brookite (orthorhombic), has been studied extensively because of its potential applications mainly in the photoelectric conversion in solar cells [1][2][3][4][5][6][7][8][9] and photocatalysis [10][11][12][13][14]. It has been pointed out that the anatase TiO 2 can prove to be the most efficient among its polymorphs if it exhibits the unique ability to absorb visible light significantly.…”