Detection of surface states associated with adsorbed hydrogen peroxide on titanium dioxide by impedance and electrolyte electroreflectance measurements

1986 ◽  
Vol 90 (13) ◽  
pp. 2805-2807 ◽  
Author(s):  
I. J. Ferrer ◽  
H. Muraki ◽  
P. Salvador
Keyword(s):  
Hydrogen Peroxide ◽  
Titanium Dioxide ◽  
Surface States ◽  
Adsorbed Hydrogen

Titanium Dioxide-Supported Sulfonated Low Rank Coal as Catalysts in the Oxidation of Styrene with Aqueous Hydrogen Peroxide

2014 ◽  
Vol 69 (5) ◽  
Author(s):  
Mukhamad Nurhadi ◽  
Jon Efendi ◽  
Lee Siew Ling ◽  
Teuku Meurah Indra Mahlia ◽  
Ho Chin Siong ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Titanium Dioxide ◽  
Catalytic Activity ◽  
Diffuse Reflectance Spectroscopy ◽  
Low Rank ◽  
Bet Surface Area ◽  
High Catalytic Activity ◽  
Low Rank Coal ◽  
X Ray Diffraction ◽  
Aqueous Hydrogen Peroxide

Titanium dioxide supported sulfonated low rank coal catalyst possesses high catalytic activity in liquid phase oxidation of styrene with aqueous hydrogen peroxide at room temperature. The catalysts were prepared by sulfonation with concentrated sulfuric acid and impregnation of titanium dioxide (500-2500 µmol). The effect of titanium dioxide impregnation and calcinations on the catalysts were studied by X-ray diffraction, UV-vis diffuse reflectance spectroscopy, Fourier transform infrared spectroscopy, BET surface area, field emission scanning electron microscopy and hydrophobicity measurement. The catalytic activity of the catalysts in the oxidation of styrene by aqueous H2O2 without calcination increased when the amount of titanium dioxide increased. Meanwhile, the catalytic activity of the catalyst calcined at 500oC for 2 h was lower than before calcination. It is suggested that the agglomeration of titanium dioxide and hydrophobicity play important role in the catalytic activity of titanium dioxide-supported sulfonated low rank coal in the oxidation of styrene with aqueous H2O2. 

Photocatalytic Oxidation of Shenfu Bituminous Coal and Xilinhaote Lignite with H2O2 over TiO2

2011 ◽  
Vol 233-235 ◽  
pp. 1684-1689 ◽  
Author(s):  
Heng Shen Xie ◽  
Zhi Min Zong ◽  
Qing Wei ◽  
Pei Zhi Zhao ◽  
Jian Jun Zhao ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Titanium Dioxide ◽  
Catalytic Oxidation ◽  
Photocatalytic Oxidation ◽  
Bituminous Coal ◽  
Straight Chain ◽  
Photo Catalytic Oxidation ◽  
Alkyl Side Chains ◽  
Lignite Coal ◽  
Oxidation Effect

Shenfu bituminous coal (SFBC) and Xilinhaote lignite (XL) were subject to photo-catalytic oxidation with hydrogen peroxide over titanium dioxide. The reaction mixtures were extracted with acetone exhaustively. The extracts were analyzed with FTIR and GC/MS. The results show that coals be oxidized selectively and degraded partially. Compared with the bituminite coal, the oxidation effect of the lignite coal with active hydrogens is more obvious. The alkyl side chains of the macromolecules, particularly, chains of methyl, methylene and aromatic, are the most vulnerable in relation to other compounds in coals. Moreover, the increasing of straight-chain alkanes and the decreasing of condensed nucleus in SFBC and XL through oxidation suggest that the oxidation is an effective method of coal utilization with no difficultly, also be friendly towards the environment after treated as well as in the process of the treatment.

scholarly journals Effect of two formulations of 10% sodium ascorbate on fracture resistance of endodontically treated tooth submitted to dental bleaching with hydrogen peroxide associated titanium dioxide nanoparticles

2014 ◽  
Vol 2 (1) ◽  
pp. 13
Author(s):  
Francisco Carlos Bontorim ◽  
Milton Carlos Kuga ◽  
Sabrina Spinelli Cioffi ◽  
Marcus Vinicius Reis Só ◽  
Gisele Faria ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Hydrogen Peroxide ◽  
Titanium Dioxide ◽  
Fracture Resistance ◽  
Composite Resin ◽  
Positive Control ◽  
Sodium Ascorbate ◽  
Resistance Testing ◽  
Dental Bleaching ◽  
Endodontically Treated Tooth

PURPOSE: This study evaluated the effect of 10% sodium ascorbate (10SA), in gel (10SAg) or aqueous solution (10SAs) formulations, on fracture resistance of endodontically treated tooth submitted to dental bleaching procedures with 15% hydrogen peroxide associated with titanium dioxide (15HP-TiO2) nanoparticles and photoactivated by LED-laser. MATERIAL AND METHODS: Forty maxillary premolars were endodontically-treated and embedded in acrylic resin up to the cement-enamel junction. The specimens were divided into four groups (n=10): G1 (negative control): no bleaching, coronal access restored with composite resin; G2 (positive control): three dental bleaching  sessions using 15HP-TiO2 and LED-laser photoactivation and restored with composite resin (positive control); G3 (10SAg): similar procedures to G2, but applied  10SA, in gel formulation, for 24 hours before restoration; G4 (10SAs): similar procedures to G3, but applied  10SA, in aqueous solution formulation.  The 15HP-TiO2 was applied on buccal and lingual surfaces of the crown tooth and inside the pulp chamber and photoactivated by LED-laser. Between each bleaching session, the teeth were maintained in artificial saliva, at 37oC, for 7 days. In sequence, the teeth were submitted to fracture resistance testing using an eletromechanical machine test. The data was analyzed using Kruskal Wallis test (p = 0.05) RESULTS: There are no differences significant among the groups in relation to fracture resistance of endodontically treated teeth (p>0.05). CONCLUSIONS: The use of 10% sodium ascorbate, in gel or aqueous solution formulations, did not interfered on the fracture resistance teeth after dental bleaching using 15HP-TiO2 and LED-laser photoactivation.

Highly-efficient photocatalytic hydrogen peroxide production over polyoxometalates covalently immobilized onto titanium dioxide

2020 ◽  
Vol 591 ◽  
pp. 117271 ◽  
Author(s):  
Xiaofei Wu ◽  
Xiufang Zhang ◽  
Shen Zhao ◽  
Yan Gong ◽  
Ridha Djellabi ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Titanium Dioxide ◽  
Hydrogen Peroxide Production ◽  
Highly Efficient

Photoluminescence of Laser-Synthesized Anatase Titanium Dioxide Nanopowders

2005 ◽  
Vol 494 ◽  
pp. 265-270 ◽  
Author(s):  
M. Šćepanović ◽  
Z. Dohčević-Mitrović ◽  
I. Hinić ◽  
M. Grujić-Brojčin ◽  
G. Stanišić ◽  
...  
Keyword(s):  
Grain Size ◽  
Titanium Dioxide ◽  
Light Emission ◽  
Surface States ◽  
Excitation Power ◽  
Anatase Tio2 ◽  
Tio2 Nanocrystals ◽  
Pl Spectra ◽  
Preparation Conditions ◽  
Tio2 Nanopowders

Titanium dioxide (TiO2) nanopowders were prepared by laser-induced pyrolysis. Raman scattering showed that prepared TiO2 nanocrystals have anatase TiO2 structure. Specific surface area of the powders varies from 84 to 110 m2/g, while the grain size of nanoparticles is between 30 and 70 nm, depending on preparation conditions. We measured photoluminescence (PL) spectra of TiO2 nanocrystals. Under laser irradiation with photon energy between 2.41 and 2.71 eV the TiO2 nanocrystals displayed strong visible light emission, even at excitation power as low as 0.05 W/cm2. The line shape and position of this broad luminescence band vary with excitation energy. As PL spectra of anatase TiO2 can be attributed to three kinds of physical origins (self-trapped excitons, surface states and oxygen vacancies) in this paper we try to resolve which of them are dominant for different TiO2 nanopowders of different grain size.

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