Synthesis of iron oxide nanorods via chemical scavenging and phase transformations of intermediates at ambient conditions
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- 作者：Ruchi Deshmukh ; Anurag Mehra ; Rochish Thaokar
- 关键词：Iron oxide ; Phase transformation ; Crystal consolidation ; Magnetism
- 刊名：Journal of Nanoparticle Research
- 出版年：2017
- 出版时间：January 2017
- 年：2017
- 卷：19
- 期：1
- 全文大小：
- 刊物类别：Chemistry and Materials Science
- 刊物主题：Nanotechnology; Inorganic Chemistry; Characterization and Evaluation of Materials; Physical Chemistry; Optics, Lasers, Photonics, Optical Devices;
- 出版者：Springer Netherlands
- ISSN：1572-896X
- 卷排序：19
文摘
Chemically induced shape transformations of isotropic seeds, comprised of iron oxyhydroxides and iron oxide borate into nanorods, is reported. Transient growth studies show that the nanorods are formed via phase transformation and aggregation of various metastable species. Addition of tetra-methyl-ammonium hydroxide (TMAH) to the in situ synthesized seeds ensures a typical reaction pathway that favors formation of magnetite (Fe 3O4) via the steps of chemical etching, phase transformation of intermediates, and crystal consolidation. Whereas, with addition of sodium hydroxide (NaOH), either magnetite (Fe 3O4) or a mixture of (γ-Fe 2O3 + α-FeOOH) is obtained. The shape with both the additives is always that of nanorods. When the seeds treated with TMAH were aged in an ultrasonication bath, rods with almost twice the length and diameter (length = 2800 nm, diameter = 345 nm) are obtained as compared to the sample aged without ultrasonication (length = 1535 nm, diameter = 172 nm). The morphology of nanostructures depending upon other experimental conditions such as, aging the sample at 60 ∘C, seeds synthesized under ultrasonication/ stirring or externally added are also examined and discussed in detail. All the samples show high coercivity and strong ferromagnetic behavior at room temperature and should be promising candidates as ferro-fluids for various applications.