An X-ray absorption spectroscopy study of the NiK edge in NiO-SiO2 nanocomposite materials prepared by the sol-gel method

被引:52
作者
Corrias, A
Mountjoy, G
Piccaluga, G
Solinas, S
机构
[1] Univ Cagliari, Dipartimento Sci Chim, Cittadella Univ Monserrato, I-09042 Cagliari, Italy
[2] Univ Kent, Sch Phys Sci, Canterbury CT2 7NR, Kent, England
来源
JOURNAL OF PHYSICAL CHEMISTRY B | 1999年 / 103卷 / 46期
关键词
D O I
10.1021/jp9927911
中图分类号
O64 [物理化学(理论化学)、化学物理学];
学科分类号
070304 ; 081704 ;
摘要
EXAFS (extended X-ray absorption fine structure) and XANES (X-ray absorption near edge structure) techniques have been used to study the structural evolution of nanocomposites constituted of nickel oxide nanoparticles embedded into an amorphous silica matrix during their sol-gel preparation. EXAFS data show that no interaction between the metal oxide nanoparticles and the silica network develops since the spectra of all the samples have a structure very similar to that of crystalline NiO. Quantitative information obtained from the fitting of the data using a full multiple scattering calculation shows that the reduction of the EXAFS oscillations in the nanocomposite samples is mainly related to an increase of disorder of the superficial sites while there was no evidence of a significant reduction of coordination numbers due to the size of the crystallites. XANES results support the conclusion that the structure of the nanocomposites is very similar to that of crystalline NiO.
引用
收藏
页码:10081 / 10086
页数:6
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