用正电子研究CuCl2在NaY上的扩散

用正电子湮没谱学研究了机械混合CuCl₂与NaY中CuCl₂在NaY沸石中的扩散.分别测量了不同质量比的CuCl₂-NaY(0～0.03)沸石分子筛经140℃烘烤1h;CuCl₂-NaY(0～0.05)经450℃烘烤4h;CuCl₂-NaY(0.01)经不同温度烘烤1h以及经300℃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CuCl₂在NaY沸石中的扩散变化.而对于只含少量氯化铜(0.01)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NaY外表面.

Dispersion of CuCl2 into NaY Zeolite Studied by Positrons

A series of samples, prepared from mechanical mixtures of CuCl₂ with NaY zeolite and resulting in the dispersion of CuCl₂, was studied by positron annihilation spectroscopy. We measured the positron lifetime spectroscopy as a function of the weight ratio of the CuCl₂-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 CuCl₂-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 CuCl₂ in NaY zeolite, and there was much CuCl₂ remained on the outside surface of NaY after heated at high temperature for a long time even for a few of CuCl₂.