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Structural study of surface tungstate in WO 3 Al 2 O 3 : Effects of Hydration and 18 O Exchange
Author(s) -
Stencel John M.,
Makovsky Leo E.,
Diehl J. Rodney,
Sarkus Tom A.
Publication year - 1984
Publication title -
journal of raman spectroscopy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.748
H-Index - 110
eISSN - 1097-4555
pISSN - 0377-0486
DOI - 10.1002/jrs.1250150415
Subject(s) - tungstate , calcination , raman spectroscopy , raman scattering , ion , ion exchange , analytical chemistry (journal) , sodium tungstate , materials science , chemistry , inorganic chemistry , crystallography , catalysis , tungsten , physics , optics , metallurgy , biochemistry , organic chemistry , chromatography
The Raman spectra of a series of WO 3 AI 2 O 3 catalysts containing 1‐30 wt‐% of WO 3 were investigated with respect to the effect of O 2 calcination and H 2 OD 2 O exposure. These studies showed that the frequencies of bands due to surface tungstate species can be shifted reversibly by as much as 6% of their values during alternate O 2 calcination and H 2 O exposure cycles. The exchange of 18 O for l6 O in the surface tungstate was also investigated with Raman spectroscopy and ion‐scattering spectrometry. The results were used to assign Raman bands to fundamental vibrations of the surface tungstate and to propose a mechanism of interaction between H 2 O and the surface tungstate that hitherto has not been addressed for WO 3 AI 2 O 3 .