New synthetic routes for preparing perovskites: Electrochemical oxidation and oxidation by NO2

J. C. Grenier, J. P. Doumerc, Y. Muraoka, S. Petit, M. Pouchard, A. Wattiaux

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Abstract

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 AMO3 (A = Sr, La; M = Fe1-xCox) or A2MO4+δ (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 NH+4 ions at moderate temperatures (typically T < 300°C), which allowed the destruction of NH+4 cations in situ. Topotactic reactions are described for preparing new hexagonal forms of WO3 or MoO3. The reaction process is discussed.

Original languageEnglish
Pages (from-to)9-15
Number of pages7
JournalSolid State Ionics
Volume108
Issue number1-4
Publication statusPublished - May 1 1998

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Keywords

  • Ammonium deintercalation
  • Chimie Douce processes
  • Electrochemical oxidation
  • In situ nitrogen dioxide reaction
  • Oxygen intercalation

ASJC Scopus subject areas

  • Chemistry(all)
  • Materials Science(all)
  • Condensed Matter Physics

Cite this

Grenier, J. C., Doumerc, J. P., Muraoka, Y., Petit, S., Pouchard, M., & Wattiaux, A. (1998). New synthetic routes for preparing perovskites: Electrochemical oxidation and oxidation by NO2. Solid State Ionics, 108(1-4), 9-15.