Xenon-129 NMR study of small sodium particles in NaY zeolite

The distribution of sodium metal particles inside the cavities of a NaY zeolite has been investigated using 129 Xe NMR spectroscopy. For a sample prepared by vapor-phase deposition at 520 K, the 129 Xe NMR spectrum shows three lines which are interpreted in terms of domains of a nonuniformly distributed metal particles, oxidized particles, and empty cavities. After annealing the sample at 670 K, the 129 Xe spectrum collapses to one single line, characteristic of a narrow particle size distribution. Oxidation of the sample by oxygen decreases the chemical shift of the 129 Xe NMR line, which is mainly due to a loss of paramagnetism and a volume contraction of the small sodium metal particles