| Autor: |
Ki Min Nam, Won Seok Seo, Joon T. Park, Jae Ha Shim, Hyunjoon Song |
| Rok vydání: |
2011 |
| Předmět: |
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| Zdroj: |
Chemistry - An Asian Journal. 6:1575-1581 |
| ISSN: |
1861-4728 |
| DOI: |
10.1002/asia.201100031 |
| Popis: |
A selective preparation and the formation mechanism of hexagonal and cubic CoO nanoparticles from the reaction of (CoA2) (acac = acetyla- cetonate) and amine have been investi- gated. CoO nanoparticles with a hexag- onal pyramidal shape were yielded under decomposition conditions with amine. Importantly, the addition of water altered the final phase to cubic and comprehensively changed the reac- tion mechanism. The average sizes of the hexagonal and cubic CoO nanopar- ticles could be controlled either by changing the amine concentration or by using different reaction tempera- tures. Detailed formation mechanisms are proposed on the basis of gas chro- matography-mass spectrometry data and color changes of the reaction mix- ture. The hexagonal CoO phase is ob- tained through two distinct pathways: solvolysis with CC bond cleavage and direct condensation by amine. On the other hand, the cubic CoO nanoparti- cles were synthesized by strong nucleo- philic attack of hydroxide ions from water and subsequent CC bond breaking. The resulting caboxylate ligand can stabilize a cobalt hydroxide intermediate, leading to the generation of a thermodynamically stable CoO phase. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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