Abstract
We report here the first structural characterization by Ti K-edge EXAFS and XANES of ETS-10 and aluminum-free Ti-β molecular sieves. A TS-1 sample was also studied for comparison. The near-edge spectrum of TS-1 revealed an intense pre-edge feature characteristic of Ti atoms in tetrahedral coordination. However, the pre-edge peak for ETS-10 was quite small and shifted in energy, which is consistent with the known octahedral structure surrounding Ti atoms in the material. Analysis of the EXAFS for ETS-10 revealed an average Ti-O interatomic distance of 2.00 +- 0.01 Å which is longer than the Ti-O distance (1.95Å) in anatase TiO2. For Ti-β, an intense pre-edge peak is present in the near-edge spectrum and the intensity, energy and width of this peak are the same as for TS-1. In addition, the average Ti-O interatomic distance in Ti-β and TS-1 was 1.80 +- 0.01 Å, which is significantly shorter than the distance measured in ETS-10. The EXAFS and XANES results indicate that the Ti sites in aluminum-free Ti-β are structurally identical to the tetrahedral sites in TS-1. This conclusion is supported by the similarity of the UV absorption thresholds for the two samples. X-ray absorption spectra were also recorded with methanol or 2-propanol adsorbed on the Ti-β and TS-1 molecular sieves. Alcohol adsorption decreased the intensity and broadened the Ti pre-edge peak for both samples, demonstrating a local chemical interaction with the Ti sites. Methanol adsorption lengthened the average Ti-O bond to 1.83 ± 0.01 Å. The similarity of the X-ray absorption spectra for aluminum-free Ti-β and TS-1 in the presence of alcohols suggests that the Ti sites in the two frameworks are chemically indistinguishable for vapor-phase adsorption of alcohols at low concentrations.
Similar content being viewed by others
References
B. Notari, Catal. Today 18 (1993) 163.
S. Pei, G.W. Zajac, J.A. Kaduk, J. Farber, B.I. Boyanov, D. Duck, D. Fazzini, T.I. Morrison and D.S. Yang, Catal. Lett. 21 (1993) 333.
S. Bordiga, S. Coluccia, C. Lamberti, L. Marchese, A. Zecchina, F. Boscherini, F. Buffa, F. Genoni, G. Leofanti, G. Petrini and G. Vlaic, J. Phys. Chem. 98 (1994) 4125.
C.B. Khouw, C.B. Dartt, J.A. Labinger and M.E. Davis, J. Catal. 149 (1994) 195.
M.G. Clerici and P. Ingallinia, J. Catal. 140 (1993) 71.
A. Corma, M.A. Camblor, P. Esteve, A. Martinez and J. Perez-Pariente, J. Catal. 145 (1994) 151.
T. Blasco, M.A. Camblor, A. Corma and J. Perez-Pariente, J. Am. Chem. Soc. 115 (1993) 11806.
M.W. Anderson, O. Terasaki, T. Ohsuna, A. Philippou, S.P. Mackay, A. Ferrara, J. Rocha and S. Lidin, Nature 367 (1994) 347.
M. Taramasso, G. Perego and B. Notari, US Patent 4,410,501 (1983).
US Patent appl. #08/329732 assigned to ARCO Chemical Technology, L.P.
W.W. Wendlandt and H. Hecht,Reflectance Spectroscopy (Wiley-Interscience, New York, 1966).
R.B. Greegor, F.W. Lytle, D.R. Sandstrom, J. Wong and P. Shultz, J. Non-Cryst. Sol. 55 (1983) 27.
F. Babonneau, S. Doeuff, A. Leaustic, C. Sanchez, C. Cartier and M. Verdaguer, Inorg. Chem. 27 (1988) 3166.
C.A. Yarker, P.A.V. Johnson, A.C. Wright, J. Wong, R.B. Greegor, F.W. Lytle and R.N. Sinclair, J. Non-Cryst. Sol. 79 (1986) 117.
G.A. Waychunas, Am. Miner. 72 (1987) 849.
Z. Liu and R.J. Davis, J. Phys. Chem. 98 (1994) 1253.
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Davis, R.J., Liu, Z., Tabora, J.E. et al. X-ray absorption spectroscopy of Ti-containing molecular sieves ETS-10, aluminum-free Ti-β, and TS-1. Catal Lett 34, 101–113 (1995). https://doi.org/10.1007/BF00808327
Received:
Accepted:
Issue Date:
DOI: https://doi.org/10.1007/BF00808327