Characterization of LaCoO3 powders obtained by water-based sol–gel method with citric acid
✍ Scribed by Luminita Predoana; Barbara Malic; Marija Kosec; Mariana Carata; Monica Caldararu; Maria Zaharescu
- Publisher
- Elsevier Science
- Year
- 2007
- Tongue
- English
- Weight
- 691 KB
- Volume
- 27
- Category
- Article
- ISSN
- 0955-2219
No coin nor oath required. For personal study only.
✦ Synopsis
LaCoO 3 -based materials are studied because they exhibit interesting, electrical, magnetic and catalytic properties. In this contribution, LaCoO 3 powders were synthesized by sol-gel method in aqueous medium starting from metal nitrates or acetates, and citric acid as the chelating agent at room temperature. The relation between the reactions in solution, crystallization pathway and morphology is discussed. The dried powders were amorphous. Their thermal decomposition occurs stepwise upon heating to 400 • C for nitrate or 500 • C for acetate-based precursors, respectively. Pure perovskite LaCoO 3 phase is formed after heating at 600 • C in the case of nitrates while in the case of acetates separation of phases occurs when 2 mol of citric acid are used. The choice of the precursor influences the morphology of the powders heated at 600 • C. The nitrate-based powders are composed of agglomerates of fine particles while the acetate-based powders mainly consist of gel fragments. Some preliminary electrical and catalytic properties are also presented.