Abstract
A NaY zeolite has been reacted with sodium or rubidium metal vapor. Exposure of the zeolite to a high Na concentration leads to a single ESR narrow line which is attributed to Na small metallic particles.inside the zeolite cavities, whereas in the case of highly Rb-loaded zeolite, no signal has been detected. The ESR signal line width shows no temperature dependence in the range 4-300 K, indicating a quenching of the bulk metal relaxation mechanisms. The signal intensity obeys Curie's law in the same temperature range, in agreement with theoretical models for small metal particles. The concentration dependence of sodium on the zeolite NaY loaded with Na was studied by 23Na NMR. 23Na and 87Rb NMR spectra were also obtained for the Rb-loaded NaY zeolite; the spectra were run at different temperatures (260-300 K). The number of spectral lines obtained can be explained by the presence of two phases in the temperature range 260-300 K; the formation of a Na/Rb alloy is also postulated on the basis of the measured Knight shifts.