ESR and NMR studies of sodium and rubidium loaded in NaY zeolite cavities
ESR and NMR studies of sodium and rubidium loaded in NaY zeolite cavities
复制标题
NaY 沸石空腔中负载的钠和铷的 ESR 和 NMR 研究
DOI：
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发表时间：
1993
期刊：
影响因子：
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通讯作者：
G. Feio
中科院分区：
文献类型：
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作者：
E. Trescos;F. Rachdi;L. C. Ménorval;F. Fajula;T. Nunes;G. Feio
NaY沸石已与钠或铷金属蒸气反应。将沸石暴露于高 Na 浓度会导致单个 ESR 窄线，这归因于沸石腔内的 Na 小金属颗粒，而在高负载 Rb 的沸石的情况下，没有检测到信号。 ESR 信号线宽度在 4-300 K 范围内没有表现出温度依赖性，表明块体金属弛豫机制发生淬火。在相同温度范围内信号强度服从居里定律，与小金属颗粒的理论模型一致。通过 23Na NMR 研究了钠对负载 Na 的 NaY 沸石的浓度依赖性。还获得了负载 Rb 的 NaY 沸石的 23Na 和 87Rb NMR 谱；光谱在不同温度（260-300 K）下运行。获得的谱线数量可以通过 260-300 K 温度范围内存在两相来解释； Na/Rb 合金的形成也是基于测量的奈特位移而假设的。
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.