Skip to main content Accessibility help
×
Home

Synthesis of Porous Transition Metal Oxides by the Salt-Gel Method

  • Andreas Stein (a1), Mark Fendorf (a2), Thomas P. Jarvie (a3), Karl T. Mueller (a3), Maurie E. Garcia (a3) and Thomas E. Mallouk (a3)...

Abstract

Composites of surfactants with certain transition metal oxides can be arranged into periodic arrays with giant tunnel structures. Transmission electron micrographs of these structures resemble images of mesoporous silicate molecular sieves synthesized in the presence of surfactants. However, data in this study lead to the conclusion that Keggin-ions of the type (H2W12O40)6- are formed during the hydrothermal synthesis of a cetyltrimethylammonium/tungstate composite. These cluster anions are not connected to each other. Removal of the organic template therefore results in the collapse of the tunnel structures.

A strategy has been developed which uses pre-arranged surfactant-salt structures as precursors for microporous and mesoporous framework materials. Transition metal silicates with long-range structural order have been synthesized by reacting surfactant salts of niobotungstate clusters with tetraethylorthosilicate to form a salt-gel. Infrared and solid-state NMR double resonance spectra indicate that, in addition to linkages between silicate tetrahedra, niobium-oxygen-silicon linkages have been formed in this reaction. Removal of the cationic surfactants by acid-extraction has resulted in porous structures with surface areas up to 265 m2/g.

Copyright

References

Hide All
1. Huo, Q. et al. , Chem. Mater. 6, 1176 (1994).
2. McMonagle, J. B., Moffat, J. B., J. Colloid Interface Sci. 70, 265 (1979).
3. Whittingham, M. S., Li, J., Guo, J. D., Zavalij, P., Materials Science Forum 152–153, 99 (1994).
4. Stein, A., Fendorf, M., Jarvie, T. P., Mueller, K. T., Benesi, A. J., Mallouk, T. E., Chem. Mater., in press.
5. Rocchiccioli-Deltcheff, C., Thouvenot, R., Franck, R., Spectrochim. Acta 32A, 587 (1976).
6. Monnier, A. et al. , Science 261, 1299 (1993).
7. Pope, M. T., Heteropoly and Isopoly Oxometalates, (Springer-Verlag, Berlin, 1983).
8. Klemperer, W. G., in Inorganic Syntheses, edited by Ginsberg, A. P. (John Wiley & Sons, New York, 1990), pp. 71135.
9. Smit, J.v. R., Nature 181, 1530 (1958).
10. McMonagle, J. B., Moffat, J. B., J. Catal. 91, 132 (1985).
11. Day, V. W., Klemperer, W. G., Schwartz, C., J. Am. Chem. Soc. 109, 6030 (1987).
12. Choisnet, J., Nguyen, N., Raveau, B., Gabelica-Robert, M., Tarte, P., J. Solid State Chem. 26, 83 (1978).
13. Vega, A. J., Scherer, G. W., J. Non-Cryst. Solids 111, 153 (1989).

Metrics

Full text views

Total number of HTML views: 0
Total number of PDF views: 0 *
Loading metrics...

Abstract views

Total abstract views: 0 *
Loading metrics...

* Views captured on Cambridge Core between <date>. This data will be updated every 24 hours.

Usage data cannot currently be displayed