May, 1998
New synthetic routes for preparing perovskites - Electrochemical oxidation and oxidation by NO2
SOLID STATE IONICS
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- Volume
- 108
- Number
- 1-4
- First page
- 9
- Last page
- 15
- Language
- English
- Publishing type
- Research paper (scientific journal)
- DOI
- 10.1016/S0167-2738(98)00012-5
- Publisher
- ELSEVIER SCIENCE BV
Two new synthetic low temperature routes for preparing perovskite-related materials, especially metastable phases are depicted. The first one, the electrochemical oxidation, uses the electric field as the driving force for intercalating oxygen atoms within parent oxide networks. The reaction is achieved under anodic potential, in alkaline solution (1 M KOH or NaOH), at room temperature, in air. This process has been used for preparing various perovskite compounds such as AMO(3) (A = Sr, La; M = Fe1-x Co-x) or A(2)MO(4+delta) (A = La, Nd, Sr). The most relevant results are reported. Potentiostatic and galvanostatic experiments have shown that the amount of intercalated oxygen can be controlled and that the process is reversible. Structural as well as electronic aspects of the oxygen intercalation are discussed and a reaction mechanism is proposed. The second route is based on the exothermic reaction of nitrogen dioxide NO2 with NH4+ ions at moderate temperatures (typically T < 300 degrees C), which allowed the destruction of NH4+ cations in situ. Topotactic reactions are described for preparing new hexagonal forms of WO3 or MoO3. The reaction process is discussed. (C) 1998 Elsevier Science B.V. All rights reserved.
- Link information
- ID information
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- DOI : 10.1016/S0167-2738(98)00012-5
- ISSN : 0167-2738
- Web of Science ID : WOS:000073790600003