Intrazeolite semiconductors: sup 23 Na MAS NMR, Tl sup + luminescence quenching, and far-IR studies of acid-base precursor chemistry in zeolite Y

Journal Article · Thu Nov 14 04:00:00 EST 1991 · Journal of Physical Chemistry; (United States)

DOI:https://doi.org/10.1021/j100176a077· OSTI ID:7273812

McMurray, L; Holmes, A J; Kuperman, A; Ozin, G A; Oezkar, S ^[1]

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1. Univ. of Toronto, Ontario (Canada)

Proton-loaded zeolites, prepared from fully dehydrated zeolites and gaseous, anhydrous Bronsted acids, represent an important step in the synthesis of intrazeolite semiconductor quantum supralattices. Adsorption-induced {sup 23}Na MAS NMR chemical shifts, far-IR Na{sup +} and Tl{sup +} translatory mode frequency shifts, and Tl{sup +} luminescence quenching effects were chosen as probes of cation-anion interaction in these materials. Samples of zeolite Y with various loadings of Tl{sup +} were prepared via aqueous ion-exchange techniques. The samples were characterized by powder X-ray diffraction and far-IR spectroscopy. Luminescence measurements revealed Tl{sup +} excitation and emission bands in the UV spectral region. Exposure of thallium Tl(I) zeolite Y to anhydrous HBr quenched the luminescence intensity. The intensity quenching followed Stern-Volmer quenching kinetics. Preliminary luminescence lifetime studies of this system supported a static ion pair quenching model. Compelling additional evidence in favor of cation-anion pair formation comes from the observation of {alpha}-cage site-specific {sup 23}Na MAS NMR chemical shifts in HBr/Na{sub 56}Y compared to virgin Na{sub 56}Y. The relevance of these observations for proton-loaded zeolite Y to the acid-base precursor chemistry involved in the synthesis of semiconductor nanostructures encapsulated in zeolite Y is critically discussed.

• OSTI ID: 7273812
• Journal Information: Journal of Physical Chemistry; (United States), Journal Name: Journal of Physical Chemistry; (United States) Vol. 95:23; ISSN 0022-3654; ISSN JPCHA
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201* -- Chemical & Physicochemical Properties
400500 -- Photochemistry
ABSORPTION SPECTROSCOPY
ALKALI METAL ISOTOPES
ANIONS
BROMINE COMPOUNDS
CATIONS
CHARGED PARTICLES
CHEMICAL PREPARATION
COHERENT SCATTERING
DATA
DIFFRACTION
ELECTROMAGNETIC RADIATION
ELEMENTS
EXPERIMENTAL DATA
FAR INFRARED RADIATION
HALOGEN COMPOUNDS
HYDROBROMIC ACID
HYDROGEN COMPOUNDS
INFORMATION
INFRARED RADIATION
INFRARED SPECTRA
INORGANIC ACIDS
INORGANIC ION EXCHANGERS
ION EXCHANGE MATERIALS
IONS
ISOTOPES
LIGHT NUCLEI
LUMINESCENCE
MAGNETIC RESONANCE
MATERIALS
METALS
MINERALS
MOLECULAR STRUCTURE
NUCLEAR MAGNETIC RESONANCE
NUCLEI
NUMERICAL DATA
ODD-EVEN NUCLEI
QUENCHING
RADIATIONS
RESONANCE
SCATTERING
SEMICONDUCTOR MATERIALS
SILICATE MINERALS
SODIUM 23
SODIUM ISOTOPES
SPECTRA
SPECTROSCOPY
STABLE ISOTOPES
SYNTHESIS
THALLIUM
X-RAY DIFFRACTION
ZEOLITES