用正电子研究CuCl_2在NaY上的扩散

Dispersion of CuCl_2 into NaY Zeolite Studied by Positrons

用正电子湮没谱学研究了机械混合 Cu Cl2 与 Na Y中 Cu Cl2 在 Na Y沸石中的扩散 .分别测量了不同质量比的 Cu Cl2 -Na Y( 0～ 0 .0 3)沸石分子筛经 1 4 0℃烘烤 1 h;Cu Cl2 -Na Y( 0～ 0 .0 5 )经 4 5 0℃烘烤 4 h;Cu Cl2 -Na Y( 0 .0 1 )经不同温度烘烤 1 h以及经 30 0℃下烘烤烘不同时间后的正电子寿命谱 .所有谱中都出现了 5(或 4 )个寿命分量 ,其第 3,4 ,5寿命分量分别与 β笼、超笼及沸石微粒界面空间的大小和数量相关 .实验表明 ,正电子湮没谱学可敏感地探测出少量 Cu Cl2 在 Na Y沸石中的扩散变化 .而对于只含少量氯化铜 ( 0 .0 1 )的情况 ,虽经高温长时间烘烤 ,但仍有相当数量的氯化铜存在于 Na Y外表面 .

A series of samples, prepared from mechanical mixtures of CuCl 2 with NaY zeolite and resulting in the dispersion of CuCl 2, was studied by positron annihilation spectroscopy. We measured the positron lifetime spectroscopy as a function of the weight ratio of the CuCl 2-NaY zeolite heated at 140 ℃ for 1 h as well as at 450 ℃ for 4 h, respectively. We also measured it as a function of the heated temperature of 1 h, and as a function of the time heated at 300 ℃ for CuCl 2-NaY(mass ratio 0.01). All lifetime spectras were resolved into five(or four) components, in which the third, the fourth and the fifth components were related to the annihilation in β cage, supercage and interface void, respectively. The experimental results showed that positron annihilation spectroscopy was sensitive to probe the change of the dispersion of a few of CuCl 2 in NaY zeolite, and there was much CuCl 2 remained on the outside surface of NaY after heated at high temperature for a long time even for a few of CuCl 2 .