Preparation of nanoscopic mixed-metal oxides by sonolysis of M(acac)3 complexes
| Authors | |
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| Year of publication | 2006 |
| Type | Article in Proceedings |
| Conference | Abstracts of International Conference NANO 06 |
| MU Faculty or unit | |
| Citation | |
| Field | Inorganic chemistry |
| Keywords | Sonochemistry; Iron; Oxides; Nanoparticles |
| Description | We prepared nanoscopic particles of Fe2O3 and CoFe2O4 by sonolysis of individual 2,4-pentanedionato complexes, M(acac)n, M = Fe, Co, n = 2, 3; and their mixtures. The reactions were carried out under anhydrous conditions and with variable amounts of added water. The organics content and the BET surface area of the oxide nanoparticles can thus be controlled. SEM was used to examine particle shape, size, and size distribution. Iron oxide product featured nanoscopic composite particles of a uniform size distribution and nearly spherical shapes with an estimated diameter of 20 nm. The organic components of the powders were identified by IR as acetate groups. TEM evidenced the amorphous nature of some of the oxide products. The Mössbauer spectra of iron oxide nanoparticles displayed their superparamagnetic properties. Temperature-dependent Mössbauer spectra demonstrate a very narrow magnetic transition with an unusually low transition temperature around 25 K reflecting the system of magnetically non-interacting ultrasmall particles with a narrow size distribution. Thermal behavior of the powders was studied by TG, magnetic TG, DTA, and DSC analysis. HT XRD revealed on heating the increase in particle diameter and crystallization. The presence of water in the reaction mixture was found to lower the organics content and increase the BET surface area. |
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