Crystal Structure Controlled Synthesis of Titania Nanocrystals in Liquid Media at Low Temperature

2006 ◽  
Vol 11-12 ◽  
pp. 3-6
Author(s):  
Li Jie Shi ◽  
Ru Yang ◽  
Tao Liu ◽  
Tian Dou Hu
Keyword(s):  
Sulfuric Acid ◽  
Low Temperature ◽  
Acid Solution ◽  
Anatase Phase ◽  
Grazing Incidence ◽  
Rutile Phase ◽  
Liquid Media ◽  
Rutile Tio2 ◽  
Coordination Numbers ◽  
Higher Temperature

High concentrated hydrochloric/nitric/sulfuric acid were used to dissolve Ti(OH)4 produced with TiOSO4. It was found that, titania, from pure rutile phase to anatase-rutile mixed phase to pure anatase phase have been synthesized at low temperature in liquid media through controlling the hydrolyzation conditions. The phase composition and the special surface area of nanometer titania powder were characterized by means of XRD and BET. The K-edge fine structure of Ti atom sites of rutile TiO2 was investigated with grazing incidence reflection mode XAFS (EXAFS and XANES) spectroscopy. The well-crystal rutile TiO2 with fine particle size and high specific surface (above200m2/g) was formed at low temperature below 80°C, while the anatase TiO2 was formed at higher temperature in hydrochloric or nitric acid solution. But in sulfuric acid solution the crystal phase was always anatase at any temperatures. The EXAFS and XANES result showed that the order of the lattice, the coordination numbers of the Ti atom for the first shell, the second shell and the third shell as well as the relative intensity of K-preedge three peaks increased with the increase of the rutile TiO2 nanoparticle size.

Dyeing Properties of Chitosan-Sulfamic Acid Solution Treated Wool with Silane Coupling Agent

2011 ◽  
Vol 331 ◽  
pp. 377-381 ◽  
Author(s):  
Xue Mei He ◽  
Kong Liang Xie
Keyword(s):  
Low Temperature ◽  
Acid Solution ◽  
Crosslinking Agent ◽  
Sulfamic Acid ◽  
Weak Acid ◽  
Color Strength ◽  
Surface Appearance ◽  
Wool Fabrics ◽  
Wool Fibers ◽  
Higher Temperature

In this study, wool fabrics were treated with different concentration of chitosan sulfamic acid solution under using 3-glycidyloxypropyltrimethoxysilane (GPTMS) as a crosslinking agent. The structure of treated wool fabrics was investigated by SEM, DSC-TG. Treated wool fibers had a irregular surface appearance, showed the presence of amounts of Nano SiO2 and their aggregates deposited onto surface of wool fibers. The thermal properties were obviously enhanced. Treated wool fabrics is more stable in higher temperature than that of untreatment. Treated wool fabrics were dyed with weak acid red B, and dyeing behaviour were studied by means of by light reflectance measurements. The color strength (K/S value) of treated wool fabrics obviousily increased from 5.33 to 31.68 by comparison with the untreatment. As a result, it can be concluded that the chitosan sulfamic acid solution with GPTMS treatment could improve the weak acid red B low temperature dyeing on wool. Further, low temperature dyeing of wool fabrics with chitosan-sulfamic acid is safe, so the results obtained are quite promising as a basis for possible future industrial application.

Effect of Matrix on Phase Formation of Nanometer TiO2 Film

2010 ◽  
Vol 658 ◽  
pp. 61-64
Author(s):  
Zhen Yan Deng ◽  
Li Li Zhu ◽  
Wei Zhuo Gai ◽  
José Maria F. Ferreira
Keyword(s):  
Phase Formation ◽  
Tio2 Film ◽  
Glass Matrix ◽  
Anatase Phase ◽  
Rutile Phase ◽  
Moderate Temperature ◽  
Tio2 Films ◽  
Porous Structures ◽  
Rutile Tio2

TiO2 films were prepared by infiltrating a titanium (IV) butoxide solution to the porous structures of glass and rutile TiO2, respectively, then dried and calcined at a moderate temperature of 550°C. Well-characterized porous nanometer TiO2 films were formed. Nanometer TiO2 film on glass matrix has an anatase phase, while that on rutile TiO2 has a rutile phase. These indicate that the phase formation of nanometer TiO2 could be tailored by the different matrices.

scholarly journals Effect of Cr\(^{3+}\) Concentration and Heat-treating Temperature on Structural Property of Cr\(^{3+}\)- doped TiO\(_2\) Nanowires Synthesized by Hydrothermal Method

2015 ◽  
Vol 24 (4) ◽  
pp. 353
Author(s):  
Trinh Thi Loan ◽  
Nguyen Ngoc Long
Keyword(s):  
Hydrothermal Method ◽  
Raman Spectra ◽  
Anatase Phase ◽  
Heat Treating ◽  
Rutile Phase ◽  
High Heat ◽  
Host Lattice ◽  
Rutile Tio2 ◽  
Dioxide Powder ◽  
Raman Modes

Anatase Ti1-xCrxO2 nanowires with Cr3+ dopant contents ranging from x = 0 to 0.1 have been successfully synthesized by hydrothermal method. The nanowires were prepared from anatase titanium dioxide powder (TiO2), chrome nitrate (Cr(NO3)3), and sodium hydroxide (NaOH). The effect of the Cr3+ concentration and heat-treating temperature on structure, morphology of the synthesized Ti1-xCrxO2 samples has been studied by X-ray diffraction, scanning electron microscopy and Raman scattering. At low heat-treating temperature (≤ 600 oC), the samples exhibited anatase phase and in the Raman spectra of samples with x ≥ 0.01 exhibited a new series peak at 120, 236, 250, 292, 362, 430, 467 and 550 cm-1, which were assigned to the localized vibrational modes related to the complexes containing Cr3+ ion. But at high heat-treating temperature (1100 oC), the samples exhibited rutile phase, in the Raman spectra the above-mentioned peak series did not appear, instead of this, only observed shifting and broadening of characteristic Raman modes (Eg and M) for rutile TiO2 with increasing Cr3+ dopant content, which proves that the Cr3+ ions have replaced the Ti4+ ions in the rutile TiO2 host lattice. The lattice constants of both the rutile and anatase TiO2 crystallites have been hardly affected by Cr3+ ions dopant contents.

Unconventional Low-Temperature Luminescence Kinetics in Micro- and Nanopowders of the Anatase Phase of Titanium Dioxide

JETP Letters ◽  
2020 ◽  
Vol 112 (8) ◽  
pp. 471-477
Author(s):  
V. S. Krivobok ◽  
A. V. Kolobov ◽  
S. E. Dimitrieva ◽  
D. F. Aminev ◽  
S. I. Chentsov ◽  
...  
Keyword(s):  
Titanium Dioxide ◽  
Low Temperature ◽  
Anatase Phase ◽  
Luminescence Kinetics

scholarly journals Rapid Growth of TiO2 Nanoflowers via Low-Temperature Solution Process: Photovoltaic and Sensing Applications

Materials ◽  
2019 ◽  
Vol 12 (4) ◽  
pp. 566 ◽  
Author(s):  
M. Akhtar ◽  
Ahmad Umar ◽  
Swati Sood ◽  
InSung Jung ◽  
H. Hegazy ◽  
...  
Keyword(s):  
Low Temperature ◽  
Anatase Phase ◽  
Three Dimensional ◽  
Solution Process ◽  
Dye Sensitized Solar Cell ◽  
Sensor Applications ◽  
Dye Sensitized ◽  
Sensing Applications ◽  
Density Growth ◽  
Temperature Solution

This paper reports the rapid synthesis, characterization, and photovoltaic and sensing applications of TiO2 nanoflowers prepared by a facile low-temperature solution process. The morphological characterizations clearly reveal the high-density growth of a three-dimensional flower-shaped structure composed of small petal-like rods. The detailed properties confirmed that the synthesized nanoflowers exhibited high crystallinity with anatase phase and possessed an energy bandgap of 3.2 eV. The synthesized TiO2 nanoflowers were utilized as photo-anode and electron-mediating materials to fabricate dye-sensitized solar cell (DSSC) and liquid nitroaniline sensor applications. The fabricated DSSC demonstrated a moderate conversion efficiency of ~3.64% with a maximum incident photon to current efficiency (IPCE) of ~41% at 540 nm. The fabricated liquid nitroaniline sensor demonstrated a good sensitivity of ~268.9 μA mM−1 cm−2 with a low detection limit of 1.05 mM in a short response time of 10 s.

scholarly journals Preparation and High-Throughput Testing of TiO2-Supported Co Catalysts for Fischer‒Tropsch Synthesis

Catalysts ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 352
Author(s):  
Christian Schulz ◽  
Peter Kolb ◽  
Dennis Krupp ◽  
Lars Ritter ◽  
Alfred Haas ◽  
...  
Keyword(s):  
High Throughput ◽  
Anatase Phase ◽  
Rutile Phase ◽  
Tropsch Synthesis ◽  
Performance Tests ◽  
Fischer Tropsch ◽  
Fischer Tropsch Synthesis ◽  
Co Catalysts ◽  
Impregnation Technique ◽  
Co Conversion

A series of Co/TiO2 catalysts was tested in a parameters field study for Fischer‒Tropsch synthesis (FTS). All catalysts were prepared by the conventional impregnation technique to obtain an industrially relevant Co content of 10 wt % or 20 wt %, respectively. In summary, 10 different TiO2 of pure anatase phase, pure rutile phase, as well as mixed rutile and anatase phase were used as supports. Performance tests were conducted with a 32-fold high-throughput setup for accelerated catalyst benchmarking; thus, 48 experiments were completed within five weeks in a relevant operation parameters field (170 °C to 233.5 °C, H2/CO ratio 1 to 2.5, and 20 bar(g)). The most promising catalyst showed a CH4 selectivity of 5.3% at a relevant CO conversion of 60% and a C5+ productivity of 2.1 gC5+/(gCo h) at 207.5 °C. These TiO2-based materials were clearly differentiated with respect to the application as supports in Co-catalyzed FTS catalysis. The most prospective candidates are available for further FTS optimization at a commercial scale.

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