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DOI: 10.1039/A809810G (Paper) Reference Section for: J. Mater. Chem., 1999, 9, 1299-1305

A structural study of (TiO2)x(SiO2)1–x (x=0.18, 0.30 and 0.41) xerogels prepared using acetylacetone

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David M. Pickup, Gavin Mountjoy, Graham W. Wallidge, Ruth Anderson, Jacqui M. Cole, Robert J. Newport and Mark E. Smith

Abstract

A combination of 29Si and 17O MAS NMR, EXAFS and FTIR spectroscopy have been used to study the atomic structure of (TiO2)x(SiO2)1–x (x=0.18, 0.30 and 0.41) xerogels prepared using an acetylacetone stabilised Ti(OPri)4 precursor. In the as-prepared materials, Ti is present in a distorted octahedral coordination with a significant proportion still complexed by acetylacetone. For the first time in such an amorphous solid, a 17O NMR resonance has been observed at 110 ppm which is attributed to (O5)Ti-O-Si groups. Heat treatment of these xerogels tends to convert TiO6 into TiO4 where the Ti is substituted into the silica network. Our results are in accord with previous work which suggests that the upper limit for solubility of TiO2 in SiO2 is ca. 15 mol%. Clear evidence of some phase separation in the (TiO2)0.41(SiO2)0.59 sample after heat treatment to 750[thin space (1/6-em)]°C is presented, although the 17O MAS NMR results show that the use of acetylacetone significantly increases the amount of Ti-O-Si bonding at this composition compared to samples prepared without it.

References

  1. C. J. Brinker and G. W. Scherer, Sol–Gel Science, The Physics and Chemistry of Sol–Gel Processing, Academic Press, San Diego, 1990 Search PubMed.
  2. M. Itoh, H. Hattori and K. J. Tanabe, J. Catal., 1974, 35, 225 CrossRef CAS.
  3. P. C. Schultz and H. T. Smyth, in Amorphous Materials, ed. E. W. Douglas and B. Ellis, Wiley, London, 1972 Search PubMed.
  4. B. E. Yoldas, J. Non-Cryst. Solids, 1980, 38, 81 CrossRef.
  5. P. J. Dirken, M. E. Smith and H. J. Whitfield, J. Phys. Chem., 1995, 99, 395 CrossRef CAS.
  6. R. Anderson, G. Mountjoy, M. E. Smith and R. J. Newport, J. Non-Cryst. Solids, 1998, 232–234, 72 CrossRef CAS.
  7. G. N. Vayssilov, Catal. Rev.-Sci. Eng., 1997, 93, 209 Search PubMed.
  8. M. L. Huggins, Phys. Rev., 1926, 27, 638 CrossRef.
  9. J. Méndez-Vivar, R. Mendoza-Serna, J. Gómez-Lara and R. Gavino, J. Sol–Gel Sci. Technol., 1997, 8, 235 Search PubMed.
  10. K. Nakamoto, Infrared and Raman Spectra of Inorganic and Coordination Compounds, Part B, Wiley-Interscience, New York, 1997 Search PubMed.
  11. G. Orcel, J. Phalippou and L. L. Hench, J. Non-Cryst. Solids, 1986, 88, 114 CAS.
  12. M. C. Matos, L. M. Ilharco and R. M. Almeida, J. Non-Cryst. Solids, 1992, 147/148, 232.
  13. I. M. Miranda Salvado and J. M. Fernandez Navarro, J. Non-Cryst. Solids, 1992, 147/148, 256.
  14. G. Engelhardt and D. Michel, High Resolution Solid State NMR of Silicates and Zeolites, Wiley, Chichester, 1987 Search PubMed.
  15. M. E. Smith, Appl. Magn. Reson., 1993, 4, 1 CrossRef CAS.
  16. M. E. Smith and H. J. Whitfield, J. Chem. Soc., Chem. Commun., 1994, 723 RSC.
  17. P. S. Fiske and J. F. Stebbins, Department of Environmental Sciences, Stanford University, Personal Communication.
  18. T. M. Walter, G. L. Turner and E. Oldfield, J. Magn. Reson., 1988, 76, 106 CAS.
  19. N. Binstead, J. W. Campbell, S. J. Gurman and P. C. Stephenson, EXAFS analysis programs, Daresbury Laboratory, Warrington, 1991 Search PubMed.
  20. W. C. LaCourse and S. Kim, in Science of Ceramic Chemical Processing, ed. L. L. Hench and D. R. Ulrich, Wiley, New York, 1986, p. 310 Search PubMed.
  21. F. Babonneau, S. Doeuff, A. Leaustic, C. Sanchez, C. Cartier and M. Verdaguer, Inorg. Chem., 1988, 27, 3166 CrossRef CAS.
  22. P. D. Moran, C. E. F. Rickard, G. A. Bowmaker, R. P. Cooney, J. R. Bartlett and J. L. Woolfrey, Inorg. Chem., 1998, 37, 1417 CrossRef CAS.
  23. P. Toledano, M. In and C. Sanchez, C.R. Acad. Sci., Sect. 2, 1991, 313, 1247 Search PubMed.
  24. T. E. Westre, A. Di Cicco, A. Filipponi, C. R. Natoli, B. Hedman, E. I. Solomon and K. O. Hodgson, J. Am. Chem. Soc., 1995, 117, 1566 CrossRef CAS.
  25. K. L. Walther, A. Wokaun, B. E. Handy and A. J. Baiker, J. Non-Cryst. Solids, 1991, 134, 47 CAS.
  26. J. B. Miller and E. I. Ko, J. Catal., 1996, 159, 58 CrossRef CAS.
  27. G. Mountjoy, D. M. Pickup, G. W. Wallidge, R. Anderson, J. M. Cole, R. J. Newport and M. E. Smith, Chem. Mater., 1999, in press Search PubMed.
  28. D. L. Evans, J. Non-Cryst. Solids, 1982, 52, 115 CAS.
  29. R. B. Greegor, F. W. Lytle, D. R. Sandstrom, J. Wong and P. Schultz, J. Non-Cryst. Solids, 1983, 55, 27 CAS.
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