Details
| Original language | English |
|---|---|
| Pages (from-to) | 8332-8337 |
| Number of pages | 6 |
| Journal | Journal of Materials Chemistry |
| Volume | 21 |
| Issue number | 23 |
| Early online date | 24 Jan 2011 |
| Publication status | Published - 21 Jun 2011 |
Abstract
The response of the local structure of various types of spinel aluminates, ZnAl2O4 (normal spinel), MgAl2O4 (partly inverse spinel), and Li0.5Al2.5O4 (fully inverse spinel), to mechanical action through high-energy milling is investigated by means of 27Al MAS NMR. Due to the ability of this nuclear spectroscopic technique to probe the local environment of Al nuclei, valuable quantitative insight into the mechanically induced changes in the spinel structure, such as the local cation disorder and the deformation of the polyhedron geometry, is obtained. It is revealed that, independent of the ionic configuration in the initial oxides, the mechanical action tends to randomize cations over the two non-equivalent cation sublattices provided by the spinel structure. The response of the spinels to mechanical treatment is found to be accompanied by the formation of a non-uniform core-shell nanostructure consisting of an ordered crystallite surrounded by a structurally disordered interface/surface shell region. Based on the comparative NMR studies of the non-treated and mechanically treated spinels, an attempt is made to separate the surface effects from the bulk effects in spinel nanoparticles. The non-equilibrium cation distribution and the deformed polyhedra are found to be confined to the near-surface layers of spinel nanoparticles with the thickness extending up to about 0.7 nm. The cation inversion parameter of the mechanically treated spinel is compared with that of the non-treated material at non-ambient conditions.
ASJC Scopus subject areas
- Chemistry(all)
- General Chemistry
- Materials Science(all)
- Materials Chemistry
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In: Journal of Materials Chemistry, Vol. 21, No. 23, 21.06.2011, p. 8332-8337.
Research output: Contribution to journal › Article › Research › peer review
}
TY - JOUR
T1 - High-resolution 27Al MAS NMR spectroscopic studies of the response of spinel aluminates to mechanical action
AU - Šepelák, Vladimir
AU - Bergmann, Ingo
AU - Indris, Sylvio
AU - Feldhoff, Armin
AU - Hahn, Horst
AU - Becker, Klaus Dieter
AU - Grey, Clare P.
AU - Heitjans, Paul
PY - 2011/6/21
Y1 - 2011/6/21
N2 - The response of the local structure of various types of spinel aluminates, ZnAl2O4 (normal spinel), MgAl2O4 (partly inverse spinel), and Li0.5Al2.5O4 (fully inverse spinel), to mechanical action through high-energy milling is investigated by means of 27Al MAS NMR. Due to the ability of this nuclear spectroscopic technique to probe the local environment of Al nuclei, valuable quantitative insight into the mechanically induced changes in the spinel structure, such as the local cation disorder and the deformation of the polyhedron geometry, is obtained. It is revealed that, independent of the ionic configuration in the initial oxides, the mechanical action tends to randomize cations over the two non-equivalent cation sublattices provided by the spinel structure. The response of the spinels to mechanical treatment is found to be accompanied by the formation of a non-uniform core-shell nanostructure consisting of an ordered crystallite surrounded by a structurally disordered interface/surface shell region. Based on the comparative NMR studies of the non-treated and mechanically treated spinels, an attempt is made to separate the surface effects from the bulk effects in spinel nanoparticles. The non-equilibrium cation distribution and the deformed polyhedra are found to be confined to the near-surface layers of spinel nanoparticles with the thickness extending up to about 0.7 nm. The cation inversion parameter of the mechanically treated spinel is compared with that of the non-treated material at non-ambient conditions.
AB - The response of the local structure of various types of spinel aluminates, ZnAl2O4 (normal spinel), MgAl2O4 (partly inverse spinel), and Li0.5Al2.5O4 (fully inverse spinel), to mechanical action through high-energy milling is investigated by means of 27Al MAS NMR. Due to the ability of this nuclear spectroscopic technique to probe the local environment of Al nuclei, valuable quantitative insight into the mechanically induced changes in the spinel structure, such as the local cation disorder and the deformation of the polyhedron geometry, is obtained. It is revealed that, independent of the ionic configuration in the initial oxides, the mechanical action tends to randomize cations over the two non-equivalent cation sublattices provided by the spinel structure. The response of the spinels to mechanical treatment is found to be accompanied by the formation of a non-uniform core-shell nanostructure consisting of an ordered crystallite surrounded by a structurally disordered interface/surface shell region. Based on the comparative NMR studies of the non-treated and mechanically treated spinels, an attempt is made to separate the surface effects from the bulk effects in spinel nanoparticles. The non-equilibrium cation distribution and the deformed polyhedra are found to be confined to the near-surface layers of spinel nanoparticles with the thickness extending up to about 0.7 nm. The cation inversion parameter of the mechanically treated spinel is compared with that of the non-treated material at non-ambient conditions.
UR - http://www.scopus.com/inward/record.url?scp=79954613286&partnerID=8YFLogxK
U2 - 10.1039/c0jm03721d
DO - 10.1039/c0jm03721d
M3 - Article
AN - SCOPUS:79954613286
VL - 21
SP - 8332
EP - 8337
JO - Journal of Materials Chemistry
JF - Journal of Materials Chemistry
SN - 0959-9428
IS - 23
ER -