Chemical quenching of positronium in Fe2O3/Al2O3 catalysts
Chemical quenching of positronium in Fe2O3/Al2O3 catalysts
复制标题
Fe2O3/Al2O3 催化剂中正电子素的化学猝灭
DOI：
10.1016/j.apsusc.2010.04.092
复制
发表时间：
2010-09
影响因子：
6.7
通讯作者：
Zhang, H. J.
中科院分区：
文献类型：
--
作者：
Chen, Z. Q.;Li, C.;Zhang, H. J.
以α-Fe 2 O3和γ-Al 2 O3纳米粉体为原料，采用固相反应法制备了Fe 2 O3/Al 2 O3催化剂。用正电子寿命和符合多普勒展宽湮没辐射技术研究了催化剂的微观结构和表面性质。正电子寿命谱显示了四个组成部分。两个长寿命τ 3和τ 4分别归因于Al 2 O3晶粒内部和晶粒之间两种类型孔隙中的正电子素湮灭。随着Fe_2O_3含量从3wt%增加到40wt%，寿命τ 3基本不变，最长寿命τ 4从96 ns减小到64 ns。其强度从24%急剧下降到小于8%。多普勒展宽S参数也显示出连续减小。多普勒展宽谱的进一步分析表明，随着Fe 2 O3含量的增加，p-Ps强度降低，这排除了正电子素自旋转换的可能性。因此，τ 4的减小很可能是由于正电子偶素与大孔表面的Fe离子发生化学猝灭反应所致。
Fe2O3/Al2O3catalysts were prepared by solid state reaction method using α-Fe2O3and γ-Al2O3nano powders. The microstructure and surface properties of the catalyst were studied using positron lifetime and coincidence Doppler broadening annihilation radiation measurements. The positron lifetime spectrum shows four components. The two long lifetimes τ3and τ4are attributed to positronium annihilation in two types of pores distributed inside Al2O3grain and between the grains, respectively. With increasing Fe2O3content from 3wt% to 40wt%, the lifetime τ3keeps nearly unchanged, while the longest lifetime τ4shows decrease from 96ns to 64ns. Its intensity decreases drastically from 24% to less than 8%. The Doppler broadening S parameter shows also a continuous decrease. Further analysis of the Doppler broadening spectra reveals a decrease in the p-Ps intensity with increasing Fe2O3content, which rules out the possibility of spin-conversion of positronium. Therefore the decrease of τ4is most probably due to the chemical quenching reaction of positronium with Fe ions on the surface of the large pores.
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影响因子：
3.7
作者：
Chen, ZQ;Kawasuso, A;Ohdaira, T
通讯作者：
Ohdaira, T
DOI：
10.1103/physrevb.54.1785
发表时间：
1996-07
期刊：
Physical review. B, Condensed matter
影响因子：
--
作者：
Jean;Rhee;Lou;Yen;Cao;Cheong;Gu
通讯作者：
Jean;Rhee;Lou;Yen;Cao;Cheong;Gu
影响因子：
6.7
作者：
Y. Itoh;H. Murakami;A. Kinoshita
通讯作者：
Y. Itoh;H. Murakami;A. Kinoshita
影响因子：
3.7
作者：
H. Saito;T. Hyodo
通讯作者：
H. Saito;T. Hyodo
影响因子：
2.3
作者：
ELDRUP, M;LIGHTBODY, D;SHERWOOD, JN
通讯作者：
SHERWOOD, JN