Home  About us  Contact
 

TiO2 Materials (tio2 + material)

Distribution by Scientific Domains
Chemistry100%

Selected Abstracts

Heterometal Alkoxides as Precursors for the Preparation of Porous Fe, and Mn,TiO2 Photocatalysts with High Efficiencies

CHEMISTRY - A EUROPEAN JOURNAL, Issue 35 2008
Xiao-Xin Zou
Abstract Transition-metal-doped titanium glycolates (M,TG, with M=Fe, Mn), which are the first non-stoichiometric heterometal alkoxides, have been synthesised through a solvothermal doping approach. X-ray diffraction, UV/Vis diffuse reflectance and ESR spectroscopy revealed that the dopant ion (Fe3+ or Mn2+) is substituted for Ti4+ in the TG lattice. Fe3+ prolongs the crystallisation time of Fe,TG, whereas Mn2+ has a smaller effect on the crystallisation time in comparison with Fe3+. The as-synthesised M,TG materials were used directly as single-source precursors for the preparation of metal-doped titania (M,TiO2) through a simple thermal treatment process. The as-prepared M,TiO2 materials maintain the rod-like morphology of the precursors and possess a mesoporous structure with high crystallinity. It has been proved that the dopant ions are incorporated into the TiO2 lattice at the Ti4+ positions. The photocatalytic activities of the M,TiO2 materials obtained were evaluated by testing the degradation of phenol under UV irradiation. From the photocatalytic results, it was concluded that high crystallinity, a large surface area and appropriate transition-metal-doping are all beneficial to the enhancement of the photocatalytic performance of the doped TiO2 material. In addition, it was noted that in comparison with Mn,TiO2, Fe,TiO2 shows higher photocatalytic activity due to the better inhibition effect of Fe3+ on recombination of photogenerated electron,hole pairs. In contrast to the conventional nanosized TiO2 photocatalyst, the micrometre-sized M,TiO2 particles we obtained can be easily separated and recovered after the photocatalytic reactions. [source]

Matrix-assisted laser desorption/ionisation mass spectrometry in the study of polycondensation of Ti(OBun)4 in the presence of Si(OEt)4

RAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 23 2003
Roberta Seraglia
The hydrolysis-polycondensation behaviour of alcoholic solutions containing Si(OEt)4 and Ti(OBun)4, in different molar ratios (Si/Ti,=,10,0.2), was analysed by laser desorption/ionisation (LDI) and matrix-assisted laser desorption/ionisation (MALDI) mass spectrometry. The solutions were prepared using operating conditions usually employed in the sol-gel synthesis of SiO2 -TiO2 materials. In accord with the well-known procedures for controlling the different chemical reactivities of the alkoxides, the pre-hydrolysis of the slower reacting silicon ethoxide and the chelation by acetylacetone of the faster reacting titanium butoxide were performed before mass spectrometric analysis. While LDI-MS did not provide evidence for the presence of mixed Si-Ti species in samples obtained from these reactions, MALDI-MS of samples diluted with chloroform and using 2,5-dihydroxybenzoic acid (DHB) as matrix led to detection of various oligomers with different contents of Si and Ti atoms. The results suggest that the formation of Si-Ti mixed oligomers seems to be the favoured process, especially for solutions in which one of the two components is diluted. Copyright © 2003 John Wiley & Sons, Ltd. [source]

Synthesis of Highly Stable and Crystalline Mesoporous Anatase by Using a Simple Surfactant Sulfuric Acid Carbonization Method

CHEMISTRY - A EUROPEAN JOURNAL, Issue 33 2010
Renyuan Zhang
Highly stable and crystalline mesoporous TiO2 materials have been successfully synthesized by a simple surfactant sulfuric acid carbonization method by using Pluronic triblock copolymers as a template (see figure). The surfactant template is first carbonized by H2SO4 to obtain rigid carbon on the surface of mesochannels that can then support the mesostructure during crystallization at high temperatures. [source]

Heterometal Alkoxides as Precursors for the Preparation of Porous Fe, and Mn,TiO2 Photocatalysts with High Efficiencies

CHEMISTRY - A EUROPEAN JOURNAL, Issue 35 2008
Xiao-Xin Zou
Abstract Transition-metal-doped titanium glycolates (M,TG, with M=Fe, Mn), which are the first non-stoichiometric heterometal alkoxides, have been synthesised through a solvothermal doping approach. X-ray diffraction, UV/Vis diffuse reflectance and ESR spectroscopy revealed that the dopant ion (Fe3+ or Mn2+) is substituted for Ti4+ in the TG lattice. Fe3+ prolongs the crystallisation time of Fe,TG, whereas Mn2+ has a smaller effect on the crystallisation time in comparison with Fe3+. The as-synthesised M,TG materials were used directly as single-source precursors for the preparation of metal-doped titania (M,TiO2) through a simple thermal treatment process. The as-prepared M,TiO2 materials maintain the rod-like morphology of the precursors and possess a mesoporous structure with high crystallinity. It has been proved that the dopant ions are incorporated into the TiO2 lattice at the Ti4+ positions. The photocatalytic activities of the M,TiO2 materials obtained were evaluated by testing the degradation of phenol under UV irradiation. From the photocatalytic results, it was concluded that high crystallinity, a large surface area and appropriate transition-metal-doping are all beneficial to the enhancement of the photocatalytic performance of the doped TiO2 material. In addition, it was noted that in comparison with Mn,TiO2, Fe,TiO2 shows higher photocatalytic activity due to the better inhibition effect of Fe3+ on recombination of photogenerated electron,hole pairs. In contrast to the conventional nanosized TiO2 photocatalyst, the micrometre-sized M,TiO2 particles we obtained can be easily separated and recovered after the photocatalytic reactions. [source]