Low-temperature synthesis of α-Fe2O3 nanoparticles with a closed cage structure

Wang, Xiong; Chen, Xiangying; Ma, Xuchu; Zheng, Honghe; Ji, Mingrong; Zhang, Zude

doi:10.1016/j.cplett.2003.12.074

Cited by 61 publications

(33 citation statements)

References 19 publications

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“…3. Photoluminescence spectra of Fe-containing silica layers produced from precursors with (1) and without (2-4) surfactant, with pH-value ≈ 2 (2) and ≈ 5 (3,4) at FeCl 3 :TEOS ratio 1:3 (3, 4) and 1:1 (2) annealed in air (2, 3) and H 2 (4).…”

Section: Dense Fe-containing Silica Layers On Si Substratesmentioning

confidence: 99%

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Formation of Iron-Containing Clusters in Silica of Predetermined Porosity

et al. 2005

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Iron-containing nanoparticles and clusters were formed in silica with porosity, which was predetermined by different procedures of sol-gel technology and the chemical composition of precursors. Bulk and layer-type samples of different porosity were synthesized and investigated. The morphology, magnetic, and optical properties were studied to characterize the samples and to analyze the formation of Fe-oxides. Experimental results showed that both Fe 2 O 3 and Fe 3 O 4 were formed in the samples and that their relative amount was dependent on preparation technology.

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Section: Dense Fe-containing Silica Layers On Si Substratesmentioning

confidence: 99%

“…Magnetite (Fe 3 O 4 ) nanorods and porous hematite (α-Fe 2 O 3 ) nanorods were prepared [3] through hydrolysis of FeCl 3 and FeSO 4 solutions. Nanoparticles of α-Fe 2 O 3 with a closed cage structure were formed [4] by a low-temperature hydrothermal method from aqueous solution of FeCl 3 and cetyltrimethylammonium bromide (CTAB).…”

Section: Introductionmentioning

confidence: 99%

Formation of Iron-Containing Clusters in Silica of Predetermined Porosity

et al. 2005

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“…In addition, from a mixture of FeCl 3 and water solution of CTAB, the nanoparticles of α-Fe 2 O 3 are formed [18]. Therefore, it was reasonable to expect that a silica layer with inclusions of Fe oxides could be formed by mixing TEOS sol with CTAB and Fe salts.…”

Section: Hybrid Samples Sio 2 :Fe/simentioning

confidence: 99%

“…Such a surface is expected to be formed from FeCl 3 and water solution of CTAB in silicate sol. It is known [1] that water solution of FeCl 3 is a micelle-type colloid, which forms due to a rapid hydrolysis reaction of FeCl 3 : [18]. However, at the interaction of active surfactant micelles, iron hydroxide, and CTAB, the mesa-structure of the silicate layer deforms and favourable conditions for the formation of inclusions occur [19].…”

Section: Hybrid Samples Sio 2 :Fe/simentioning

confidence: 99%

Formation and investigation of porous SiO₂films on Si

Šustavičiūtė¹,

Šimkienė²,

Sabataityte³

et al. 2004

Lith. J. Phys.

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Porous silica layers on Si substrates were produced by sol-gel spin-on technique. The structural studies and ellipsometric measurements have been carried out in order to investigate the dependence of silica properties on growth technology and thermal annealing. The dense SiO2 layers from acid tetraethoxysilane-based precursors and the layers of increased porosity obtained from precursors containing surfactant cethyltrimethylammonia bromide were investigated. The hybrid type Fe-doped silica layers were also produced and studied. The provided investigations have shown that the method used is perspective for fabrication of porous silica layers and for obtaining hybrid samples.

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“…Nanocrystalline α-Fe 2 O 3 powders have been prepared by different preparation techniques like sol-gel [12], hydrothermal [13], chemical vapor phase deposition [14], calcinations of hydroxides [15], radio frequency sputtering [16], gas condensation technique [17], and high-energy ball-milling process [18,19]. Kündig et al [20] measured the Mössbauer spectra of Fe 57 in α-Fe 2 O 3 as a function of particle size and temperature and noticed that bulk α-Fe 2 O 3 changed 2 ISRN Ceramics in the sign of the quadrupole interaction in going through the Morin transition temperature, 263 K. They reported the superparamagnetic behavior of α-Fe 2 O 3 when the particle size is less than 13 nm and as the particle size gradually increased, it became ferromagnetic.…”

Section: Introductionmentioning

confidence: 99%

Microstructure, Mössbauer, and Optical Characterizations of Nanocrystalline α-Fe2O3 Synthesized by Chemical Route

et al. 2011

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Nanocrystalline α-Fe 2 O 3 of crystallite sizes ranging from 18 nm to 54 nm has been prepared by sol gel process and postannealing the powder up to 500• C. X-ray diffraction and transmission electron microscopy images have been used for determining the average crystallite sizes of the prepared samples. The Rietveld analysis reveals that the "as-prepared" α-Fe 2 O 3 powders are not completely stoichiometric, and significant (∼20%) oxygen vacancies are noticed in the α-Fe 2 O 3 lattice. Oxygen atoms in as-prepared sample are significantly displaced and the lattice is heavily distorted. With increasing annealing temperature the lattice approaches towards the stoichiometric oxygen concentration and perfect lattice configuration. Mössbauer spectrum of the unannealed (as-prepared) α-Fe 2 O 3 sample shows the superparamagnetic behavior at room temperature whereas all annealed samples show complete ferromagnetic behavior. Optical band gaps of these nanocrystalline α-Fe 2 O 3 samples have been measured from UV-Vis spectroscopy and found to decrease from 2.65 eV to 2.50 eV, like an n-type semiconductor, with increasing annealing temperature up to 500• C.

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Low-temperature synthesis of α-Fe2O3 nanoparticles with a closed cage structure

Cited by 61 publications

References 19 publications

Formation of Iron-Containing Clusters in Silica of Predetermined Porosity

Formation of Iron-Containing Clusters in Silica of Predetermined Porosity

Formation and investigation of porous SiO₂films on Si

Microstructure, Mössbauer, and Optical Characterizations of Nanocrystalline α-Fe2O3 Synthesized by Chemical Route

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Low-temperature synthesis of α-Fe2O3 nanoparticles with a closed cage structure

Cited by 61 publications

References 19 publications

Formation of Iron-Containing Clusters in Silica of Predetermined Porosity

Formation of Iron-Containing Clusters in Silica of Predetermined Porosity

Formation and investigation of porous SiO2films on Si

Microstructure, Mössbauer, and Optical Characterizations of Nanocrystalline α-Fe2O3 Synthesized by Chemical Route

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Product

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Formation and investigation of porous SiO₂films on Si