Nature, stability and bonding of the peroxy group in peroxy titanium compounds

Deposition of thin TiO2 layers on platinum by means of cyclic voltammetry of selected complex Ti(IV) media leading to anatase

“…In the literature, numerous examples of peroxotitanium(IV) complexes with chelating ligands are known [29,30]. In the system Ti(IV)-H 2 O 2 -C 2 O 4 2− -H 2 O, the existence of the complex, in which one oxalate ligand and one peroxo ligand are coordinated to one titanium ion, is described [31]. However, the solutions consisted of oxalates and hydrogen peroxide are sufficiently stable if Ti 4+ ions, H 2 O 2 and C 2 O 4 2− ions are in the molar ratio of 1:2:2.…”

Preparation of Visible-Light Active Oxygen-Rich TiO2 Coatings Using Low Pressure Cold Spraying

“…The Raman spectra of the measured samples contain two more bands in the frequency ranges, which in the literature are ascribed to the vibration of the triangular peroxy titanyl group, in which O-O vibrations [39,52,57] or Ti-O vibrations [53,54] occur. The O-O stretching in the feedstock powder is observed at 913 cm −1 , and in coatings, it blueshifts and loses intensity more for coating sprayed at higher temperatures.…”

“…The most intense band of feedstock powder spectra is located at 531 cm −1 . The mode observed in the range of 524-529 cm −1 can be connected with the stretching vibration of Ti-O 2 2− , in which O 2 2− is bound to a single Ti 4+ center in a side-on bonding configuration [52], which is called a triangular peroxy titanyl group in some works [53]. The presence of a band at this frequency is considered to be evidence of obtaining an oxygen-rich titanium dioxide powder containing O 2 2− species incorporated during synthesis.…”

“…The O-O stretching in the feedstock powder is observed at 913 cm −1 , and in coatings, it blueshifts and loses intensity more for coating sprayed at higher temperatures. The intensity of the Ti-O vibrations in triangular titanyl groups (at ~1050 cm −1 ) [53] is also reduced due to spraying. Therefore, all three bands assigned in the powder spectrum to the triangular titanyl groups (531, 913 and 1054 cm −1 ) after spraying show a reduced intensity, indicating the thermal instability of the triangular peroxide species, which is consistent with the literature reports [53].…”

“…The intensity of the Ti-O vibrations in triangular titanyl groups (at ~1050 cm −1 ) [53] is also reduced due to spraying. Therefore, all three bands assigned in the powder spectrum to the triangular titanyl groups (531, 913 and 1054 cm −1 ) after spraying show a reduced intensity, indicating the thermal instability of the triangular peroxide species, which is consistent with the literature reports [53]. The disintegration of unstable peroxide groups is accompanied by the appearance of superoxide groups in the coatings, which is evidenced by an increase in the intensity of the 700 cm −1 band in the spectra of the 200 coating.…”