129Xe nuclear magnetic resonance studies of H-Ga-MFI zeolites

Autor:	Susan M. Bradley, Russell F. Howe
Rok vydání:	1995
Předmět:	General Engineering Analytical chemistry Oxide chemistry.chemical_element General Chemistry Nuclear magnetic resonance spectroscopy chemistry.chemical_compound Nuclear magnetic resonance Xenon chemistry Aluminium Lattice (order) General Materials Science Gallium Zeolite
Zdroj:	Microporous Materials. 4:131-139
ISSN:	0927-6513
DOI:	10.1016/0927-6513(94)00089-e
Popis:	129Xe Nuclear magnetic resonance (NMR) studies of H-Ga-MFI samples having a range of lattice and extralattice gallium contents have shown that the 129Xe NMR technique can be used as an estimate of the lattice gallium content and the extent of charge on the extralattice gallium species. The xenon chemical shift extrapolated to zero xenon coverage can be used to estimate the lattice gallium content and the extent of charge on the extralattice gallium species. The xenon chemical shift extrapolated to zero xenon coverage is linearly dependent on the lattice gallium content as determined by 29Si magic-angle spinning (MAS) NMR spectroscopy. Samples containing high concentrations of extralattice gallium showed a marked upward curvature in plots of xenon chemical shift versus xenon density at low xenon density. Steaming of the zeolites reduces the lattice gallium content and the upward curvature in the xenon chemical shift plots, consistent with hydrolysis of extralattice Ga3+ to uncharged oxide or oxyhydroxide gallium species within the zeolite pores.
Databáze:	OpenAIRE
Externí odkaz:	https://explore.openaire.eu/search/publication?articleId=doi_________::bfa61b13de2122ee3525554397f96302 https://doi.org/10.1016/0927-6513(94)00089-e Zobrazit plný text záznamu Full Text from ScienceDirect