Introduction of peroxo groups into titania: preparation, characterization and properties of the new peroxo-containing phase

Abstract

The new phase, where peroxo groups are incorporated into titania particles, along with anatase and hydrated η-TiO 2 with peroxo groups on the surface of titania nanoparticles, were prepared by introduction of H 2 O 2 into reaction mixtures while synthesizing TiO 2 from TiOSO 4 or by cold impregnation of pre-synthesized TiO 2 . The samples were studied by a complex of methods (classical and synchrotron-radiation X-ray powder diffraction, small-angle X-ray scattering, high-resolution scanning electron microscopy with energy-dispersive X-ray spectroscopy, X-ray absorption spectroscopy, IR and Raman spectroscopy, X-ray photoelectron spectroscopy, UV-vis diffuse reflectance and absorption spectroscopy, DSC). The [TiO x (O 2 ) 2-x (H 2 O) m ] phase was first structurally characterized and compared to η-TiO 2 . Most samples of H 2 O 2 -sensitized TiO 2 discolor methyl orange under visible light irradiation faster than commercial Hombikat UV100 treated with H 2 O 2 . The activity of the samples strongly relating to their phase composition was associated with existence of large amount of titanium peroxo complexes along with formation of mixed-phase samples.

Effects of Annealing Temperature on the Crystal Structure, Morphology, and Optical Properties of Peroxo-Titanate Nanotubes Prepared by Peroxo-Titanium Complex Ion

“…However, the bandgap energy was increased by annealing, as shown in Figure 8 , which might be due to the decomposition of the peroxo bond. Savinkina et al [ 48 ] reported that the peroxo bond is stable at room temperature in the air but it can be destroyed by annealing above of 200 °C, and this phenomenon was also observed in this study as mentioned above.…”

Promoting Effect of Bismuth Oxide on Palladium for Low‐Temperature Carbon Monoxide Oxidation

“…Notably, the Pd 3p 3/2 peak (BE≈532.8 eV) overlaps with the O 1s peaks. An additional peak at BE=532.4 eV is observed for Pd&Bi(1.4)/TiO 2 ‐N, which may be caused by the surface oxygen species related to Pd and Bi interfaces . The corresponding atomic compositions of the various samples are summarized in Table S2.…”

“…An additional peak at BE = 532.4 eV is ChemCatChem 2017, 9,499 -504 www.chemcatchem.org observedf or Pd&Bi(1.4)/TiO 2 -N, which may be caused by the surfaceo xygen speciesr elatedt oP da nd Bi interfaces. [41][42][43][44] The correspondinga tomicc ompositions of the various samples are summarized in Ta bleS2. Such ap eculiarity may be an origin of the high activity and stabilityf or CO oxidation on Pd&Bi(1.4)/ TiO 2 -N.…”

Hydrosols of Titanium Dioxide Nanoparticles Containing Ti(IV) Peroxo Complexes: Modification, Optical Properties, Morphology, and Bleaching Kinetics

“…As shown in our previous study [ 11 ], Ti(IV) oxide peroxide nanoparticles prepared by hydrothermal treatment from titanyl sulfate under specially selected conditions bleach (on account of the decomposition of peroxo complexes) as a result of storage at room temperature (in the dark) for a year. Moreover, it is shown that varying the time when peroxo groups are added to a reaction mixture allows one to drastically change the bleaching rate of the peroxo complexes in the composition of the resulting nanoparticles, to the point of complete termination of the process (which can be exemplified by TiO x (O 2 ) 2 – x (H 2 O) m nanoparticles, which retain their original color during both storage in the light for many years and annealing at temperatures of up to 400°C) [ 12 ]. In addition, correlations were found between the composition of the Ti(IV) peroxo complexes, the micromorphology of their thin films (as assessed by optical microscopy and scanning electron microscopy), and the temperature range of the formation of various TiO 2 polymorphs during annealing [ 13 ].…”

“…Analysis of synchrotron X-ray diffraction patterns of this phase (Kurchatov Institute National Research Center) made it possible to determine the unit-cell parameters of its orthorhombic structure: a = 3.880(5) Å, b = 11.64(2) Å, and c = 12.64(1) Å. This phase is an anatase-related superstructure and converts into anatase during prolonged annealing above 400°C [ 12 ].…”