Details
| Original language | English |
|---|---|
| Pages (from-to) | 689-701 |
| Number of pages | 13 |
| Journal | Solid State Sciences |
| Volume | 10 |
| Issue number | 6 |
| Early online date | 29 Nov 2007 |
| Publication status | Published - Jun 2008 |
Abstract
Nowadays, sol-gel procedures are well established in the synthesis of complex oxides as they allow to obtain phase pure products and to control precisely their stoichiometry. This quality makes them a tool of choice for the preparation of perovskite-type oxides. To optimize the functional properties of these materials, it is essential to set accurately their possible complex stoichiometries. However, details of the formation of the perovskite crystal remain obscure. Different stages of an ethylene-diamine-tetraacetic acid (EDTA)/citrate-gel based synthesis process for mixed conducting (Ba0.5Sr0.5)(Fe0.8Zn0.2)O3-δ of cubic perovskite structure are elucidated. The combination of analytical transmission electron microscopy with X-ray diffraction reveals that the perovskite-type oxide is formed already at moderate temperatures at around 700 °C via nanoscale solid state reactions between finely-dispersed crystalline intermediates identified as a spinel and a carbonate. The reaction scheme, however, is intricate and includes stuffed tridymite structures as transient phases. The ultrafine intermixing of extremely small reactants makes EDTA/citrate-gel based procedures superior to classical solid state routes with respect to applications that demand phase purity and stoichiometry control.
Keywords
- Carbonate, Ellingham diagram, Perovskite, Reaction mechanism, Rietveld refinement, Sol-gel synthesis, Spinel, Stuffed tridymite, Transmission electron microscopy
ASJC Scopus subject areas
- Chemistry(all)
- General Chemistry
- Materials Science(all)
- General Materials Science
- Physics and Astronomy(all)
- Condensed Matter Physics
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In: Solid State Sciences, Vol. 10, No. 6, 06.2008, p. 689-701.
Research output: Contribution to journal › Article › Research › peer review
}
TY - JOUR
T1 - The sol-gel synthesis of perovskites by an EDTA/citrate complexing method involves nanoscale solid state reactions
AU - Feldhoff, Armin
AU - Arnold, Mirko
AU - Martynczuk, Julia
AU - Gesing, Th M.
AU - Wang, Haihui
N1 - Funding Information: The authors acknowledge gratefully funding by the Deutsche Forschungsgemeinschaft (DFG) under grant FE 928-1. Thanks are given to Dr. Sebastian Hein for assistance in decarbonation experiments. Fruitful discussions with Prof. Jürgen Caro are appreciated.
PY - 2008/6
Y1 - 2008/6
N2 - Nowadays, sol-gel procedures are well established in the synthesis of complex oxides as they allow to obtain phase pure products and to control precisely their stoichiometry. This quality makes them a tool of choice for the preparation of perovskite-type oxides. To optimize the functional properties of these materials, it is essential to set accurately their possible complex stoichiometries. However, details of the formation of the perovskite crystal remain obscure. Different stages of an ethylene-diamine-tetraacetic acid (EDTA)/citrate-gel based synthesis process for mixed conducting (Ba0.5Sr0.5)(Fe0.8Zn0.2)O3-δ of cubic perovskite structure are elucidated. The combination of analytical transmission electron microscopy with X-ray diffraction reveals that the perovskite-type oxide is formed already at moderate temperatures at around 700 °C via nanoscale solid state reactions between finely-dispersed crystalline intermediates identified as a spinel and a carbonate. The reaction scheme, however, is intricate and includes stuffed tridymite structures as transient phases. The ultrafine intermixing of extremely small reactants makes EDTA/citrate-gel based procedures superior to classical solid state routes with respect to applications that demand phase purity and stoichiometry control.
AB - Nowadays, sol-gel procedures are well established in the synthesis of complex oxides as they allow to obtain phase pure products and to control precisely their stoichiometry. This quality makes them a tool of choice for the preparation of perovskite-type oxides. To optimize the functional properties of these materials, it is essential to set accurately their possible complex stoichiometries. However, details of the formation of the perovskite crystal remain obscure. Different stages of an ethylene-diamine-tetraacetic acid (EDTA)/citrate-gel based synthesis process for mixed conducting (Ba0.5Sr0.5)(Fe0.8Zn0.2)O3-δ of cubic perovskite structure are elucidated. The combination of analytical transmission electron microscopy with X-ray diffraction reveals that the perovskite-type oxide is formed already at moderate temperatures at around 700 °C via nanoscale solid state reactions between finely-dispersed crystalline intermediates identified as a spinel and a carbonate. The reaction scheme, however, is intricate and includes stuffed tridymite structures as transient phases. The ultrafine intermixing of extremely small reactants makes EDTA/citrate-gel based procedures superior to classical solid state routes with respect to applications that demand phase purity and stoichiometry control.
KW - Carbonate
KW - Ellingham diagram
KW - Perovskite
KW - Reaction mechanism
KW - Rietveld refinement
KW - Sol-gel synthesis
KW - Spinel
KW - Stuffed tridymite
KW - Transmission electron microscopy
UR - http://www.scopus.com/inward/record.url?scp=46249110362&partnerID=8YFLogxK
U2 - 10.1016/j.solidstatesciences.2007.11.030
DO - 10.1016/j.solidstatesciences.2007.11.030
M3 - Article
AN - SCOPUS:46249110362
VL - 10
SP - 689
EP - 701
JO - Solid State Sciences
JF - Solid State Sciences
SN - 1293-2558
IS - 6
ER -