Intrazeolite nonstoichiometric tungsten oxides n[WO{sub 3-x}]-Na{sub 56}Y (O < n {le} 32, O {le} x {le} 1)

Journal Article · Wed Nov 04 04:00:00 EST 1992 · Journal of the American Chemical Society

DOI:https://doi.org/10.1021/ja00049a028· OSTI ID:569220

Ozin, G A; Prokopowicz, R A ^[1]; Oezkar, S ^[2]

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1. Univ. of Toronto, Ontario (Canada)
2. Middle East Technical Univ., Ankara (Turkey)

The photooxidation of {alpha}-cage encapsulated n[W(CO){sub 6}]-Na{sub 56}Y, where O < n {le} 16 and Na{sub 56}Y denotes sodium zeolite Y, provides a mild, clean, and quantitative synthetic pathway to molecular dimension tungsten (VI) oxide moieties, encapsulated within the void structure of the zeolite Y host, according to the reaction stoichiometry n[W(CO){sub 6}]-Na{sub 56}Y+9/2nO{sub 2}{r_arrow}n[WO{sub 3}]-Na{sub 56}Y+6nCO{sub 2}. Following photooxidation, half of the {alpha}-cage void volume in the Na{sub 56}Y host is freed so that subsequent precursor (saturation level) impregnations/photooxidations can be carried out in a stepwise fashion, proceeding as n = 16, 24, 28, 30, ..., 32 per unit cell. Thermal vacuum treatment of these materials proceeds in two well-defined steps around 300 and 400 {degrees}C to yield encapsulated n[WO{sub 3-x}]-Na{sub 56}Y materials having x = 0.5 and 1, respectively. This reduction process is reversible by heating in an O{sub 2} atmosphere at 300 {degrees}C. 34 refs., 14 figs., 2 tabs.

• Sponsoring Organization: USDOE
• OSTI ID: 569220
• Journal Information: Journal of the American Chemical Society, Journal Name: Journal of the American Chemical Society Journal Issue: 23 Vol. 114; ISSN JACSAT; ISSN 0002-7863
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
40 CHEMISTRY
CHEMICAL REACTION YIELD
CRYSTAL DOPING
CRYSTAL LATTICES
CRYSTAL STRUCTURE
DIMERS
OXIDATION
PHOTOCHEMICAL REACTIONS
REDOX REACTIONS
REDUCTION
SODIUM
STOICHIOMETRY
SYNTHESIS
TUNGSTEN OXIDES
VALENCE
ZEOLITES