A reinvestigation of the preparation of tungsten oxide hydrate WO3, 1/3H2O
1995; Elsevier BV; Volume: 119; Issue: 1 Linguagem: Inglês
10.1016/0022-4596(95)80013-f
ISSN1095-726X
AutoresJ. Pfeifer, Cao Guifang, P. Tekula-Buxbaum, B.A. Kiss, M. Farkas‐Jahnke, K. Vadasdi,
Tópico(s)Catalysis and Oxidation Reactions
ResumoA reinvestigation of the synthesis procedures of WO3, 1/3H2O via the preparation and dehydration of H2WO4, H2O has been carried out in order to check the stoichiometry of WO3, 1/3H2O, the parent material of the important hexagonal WO3. The formation of WO3, 1/3H2O during dehydration reaction of H2WO4, H2O via the solution was observed to require the presence of sodium in the reaction system, resulting in sodium incorporation in the WO3, 1/3H2O phase. The minimal level of sodium in the WO3, 1/3H2O phase was found to be 160 ppm; sodium levels up to 1000–3000 ppm were also found to be incorporated in the WO3, 1/3H2O structures. A shift in the c parameter of the WO3, 1/3H2O cell has been found to be connected with the change in the concentration of incorporated sodium. The average size of the octagonal platelets of WO3, 1/3H2O was found to be connected with the sodium concentration in the solid phase. A modification in infrared absorption spectra has been observed.
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