Synthesis of magnetite nanoparticles (Fe3O4) through an ultra-sonically assisted coprecipitation method
Fe3O4 and Fe3O4@SiO2 nanoparticles were synthesized and characterized using an ultrasonically assisted co-precipitation method. Two synthesis conditions were evaluated by varying the ammonia addition rate: dropwise (6.95 mL min−1, Fe3O4-I) and instantaneous (429 mL min−1, Fe3O4-II). The resulting Fe...
| Autores: | , , , , , , |
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| Tipo de recurso: | artículo |
| Estado: | Versión aceptada para publicación |
| Fecha de publicación: | 2025 |
| País: | España |
| Institución: | Consejo Superior de Investigaciones Científicas (CSIC) |
| Repositorio: | DIGITAL.CSIC. Repositorio Institucional del CSIC |
| OAI Identifier: | oai:digital.csic.es:10261/414264 |
| Acceso en línea: | http://hdl.handle.net/10261/414264 https://www.scopus.com/inward/record.uri?eid=2-s2.0-105022190412&doi=10.1016%2Fj.ssc.2025.116219&partnerID=40&md5=82289b465f3445d986255d2024cccc70 |
| Access Level: | acceso embargado |
| Palabra clave: | Crystallinity Iron oxide nanoparticles Magnetic properties Nanocomposite Sonochemical synthesis |
| Sumario: | Fe3O4 and Fe3O4@SiO2 nanoparticles were synthesized and characterized using an ultrasonically assisted co-precipitation method. Two synthesis conditions were evaluated by varying the ammonia addition rate: dropwise (6.95 mL min−1, Fe3O4-I) and instantaneous (429 mL min−1, Fe3O4-II). The resulting Fe3O4 nanoparticles exhibited average crystallite sizes of 12.5 ± 1.2 nm (I) and 10.3 ± 1.7 nm (II). Subsequent SiO2 coating via a TEOS sol-gel route produced core-shell Fe3O4@SiO2 structures with shell thicknesses of 2.1–2.6 nm (I@SiO2) and 2.4–2.9 nm (II@SiO2). Magnetic measurements revealed saturation magnetization (Ms) values of 61.6 (I) and 66.5 emu·g−1 (II) for the uncoated samples, and 11.7 (I@SiO2) and 41.0 emu·g−1 (II@SiO2) after coating, with coercivity (Hc) ranging from 0.005 to 3.8 Oe. The blocking temperatures (TB) were 176.4–192.8 K for Fe3O4 and 132.1–161.2 K for Fe3O4@SiO2, confirming superparamagnetic behavior at room temperature. DLS analysis verified excellent colloidal stability and uniform dispersion, while FTIR spectra confirmed successful SiO2 coating and the presence of hydroxyl and silanol surface groups. The SiO2 shell improved nanoparticle stability and dispersion while slightly reducing magnetic response. These results demonstrate that controlled synthesis under ultrasonic assistance yields highly crystalline, stable Fe3O4 based nanostructures suitable for biomedical applications such as MRI contrast agents. |
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