Structure of hybrid (organic/inorganic) TiO2-SiO2 xerogels as studied by neopentane adsorption at 273 K and Ti K-edge X-ray absorption spectroscopy

Gustavo Larsen, Hugo S. Silva, Rosa Venturini De Silva

Research output: Contribution to journalArticle

9 Citations (Scopus)

Abstract

TiO2-SiO2 hybrid alcogels prepared from two different 'organic silicon' precursors, namely Me2Si(OMe)2 and (Me2SiO)3, were characterized by adsorption of neopentane at 273 K and X-ray absorption spectroscopy (XAS) at the Ti K-edge. Simultaneous fitting of the macro- and mesopore (BET), and micropore (Dubinin-Radushkevitch, DR) neopentane adsorption uptakes at 273 K provides a picture of the near-ambient pore structure of these flexible materials. Both X-ray absorption near edge structures (XANES) and EXAFS indicate that micro-segregation into small TiOx particles takes place during acid hydrolysis in the material prepared from the cyclic (Me2Si-O)3 precursor, but a higher Ti dispersion is observed in TiO2-SiO2 hybrid glasses prepared from Me2Si(OMe)2. Spectral features indicative of pentacoordinated Ti dominate the pre-edge XAS structure of the TiO2-SiO2 hybrid glass prepared from Me2Si(OMe)2.

Original languageEnglish (US)
Pages (from-to)1-11
Number of pages11
JournalJournal of Non-Crystalline Solids
Volume271
Issue number1
DOIs
StatePublished - Jun 2000

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neopentane
Xerogels
X ray absorption spectroscopy
xerogels
absorption spectroscopy
Adsorption
Glass
adsorption
X ray absorption
Pore structure
Macros
Hydrolysis
x rays
glass
Silicon
Acids
hydrolysis
porosity
acids
silicon

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Ceramics and Composites
  • Condensed Matter Physics
  • Materials Chemistry

Cite this

Structure of hybrid (organic/inorganic) TiO2-SiO2 xerogels as studied by neopentane adsorption at 273 K and Ti K-edge X-ray absorption spectroscopy. / Larsen, Gustavo; Silva, Hugo S.; Venturini De Silva, Rosa.

In: Journal of Non-Crystalline Solids, Vol. 271, No. 1, 06.2000, p. 1-11.

Research output: Contribution to journalArticle

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abstract = "TiO2-SiO2 hybrid alcogels prepared from two different 'organic silicon' precursors, namely Me2Si(OMe)2 and (Me2SiO)3, were characterized by adsorption of neopentane at 273 K and X-ray absorption spectroscopy (XAS) at the Ti K-edge. Simultaneous fitting of the macro- and mesopore (BET), and micropore (Dubinin-Radushkevitch, DR) neopentane adsorption uptakes at 273 K provides a picture of the near-ambient pore structure of these flexible materials. Both X-ray absorption near edge structures (XANES) and EXAFS indicate that micro-segregation into small TiOx particles takes place during acid hydrolysis in the material prepared from the cyclic (Me2Si-O)3 precursor, but a higher Ti dispersion is observed in TiO2-SiO2 hybrid glasses prepared from Me2Si(OMe)2. Spectral features indicative of pentacoordinated Ti dominate the pre-edge XAS structure of the TiO2-SiO2 hybrid glass prepared from Me2Si(OMe)2.",
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AB - TiO2-SiO2 hybrid alcogels prepared from two different 'organic silicon' precursors, namely Me2Si(OMe)2 and (Me2SiO)3, were characterized by adsorption of neopentane at 273 K and X-ray absorption spectroscopy (XAS) at the Ti K-edge. Simultaneous fitting of the macro- and mesopore (BET), and micropore (Dubinin-Radushkevitch, DR) neopentane adsorption uptakes at 273 K provides a picture of the near-ambient pore structure of these flexible materials. Both X-ray absorption near edge structures (XANES) and EXAFS indicate that micro-segregation into small TiOx particles takes place during acid hydrolysis in the material prepared from the cyclic (Me2Si-O)3 precursor, but a higher Ti dispersion is observed in TiO2-SiO2 hybrid glasses prepared from Me2Si(OMe)2. Spectral features indicative of pentacoordinated Ti dominate the pre-edge XAS structure of the TiO2-SiO2 hybrid glass prepared from Me2Si(OMe)2.

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