O-17 and SI-29 Solid- State NMR-Study of Atomic- Scale Structure in SOL-GEL-Prepared TIO2-SIO2 Materials

Dirken, Peter J. and Smith, Mark E. and Whitfield, Harold J. (1995) O-17 and SI-29 Solid- State NMR-Study of Atomic- Scale Structure in SOL-GEL-Prepared TIO2-SIO2 Materials. Journal of Physical Chemistry, 99 (1). pp. 395-401. ISSN 0022-3654. (The full text of this publication is not available from this repository)

The full text of this publication is not available from this repository. (Contact us about this Publication)

Abstract

Solid state O-17 and Si-29 magic angle spinning (MAS) NMR spectroscopy has been applied to the study of the structure of three Ti-Si mixed oxides and their gel precursors. Gels were prepared by the hydrolysis of tetraethyl orthosilicate (TEOS) and titanium isopropoxide (Ti(OPrn)4). Both one-stage (addition of the Ti(OPrn)4 to the TEOS) and two-stage (partial hydrolysis of the TEOS before addition of the Ti(OPrn)4) procedures were used. Si-29 MAS NMR spectra hardly show any differences between the one- and two-stage gels. All consist of Q(2), Q(3), and Q(4) SiO4 species becoming Q(4) after heat treatment at 600 degrees C. This study shows that O-17 MAS NMR is a valuable tool in the characterization of amorphous oxides and that it is much more informative than Si-29 MAS NMR. O-17 MAS NMR shows that titanium is incorporated only as Ti-O-Si bonds in a two-stage gel, whilst samples that show phase separation alsb have Ti-O-Ti bonds. Ti-O-Si linkages persist until 600 degrees C and in conjunction with the Si-29 NMR data indicate that titanium enters the silica network. The assignment of the Ti-O-Si resonance is confirmed by studying the mineral fresnoite (Ba2TiSi2O8).

Item Type: Article
Subjects: Q Science > QD Chemistry
Divisions: Faculties > Science Technology and Medical Studies > School of Engineering and Digital Arts
Depositing User: P. Ogbuji
Date Deposited: 03 Jun 2009 08:39
Last Modified: 09 Jun 2014 10:33
Resource URI: http://kar.kent.ac.uk/id/eprint/19492 (The current URI for this page, for reference purposes)
  • Depositors only (login required):