Surfactant-Assisted Combustion Method for the Synthesis of α-Fe 2 O 3 Nanocrystalline Powders (original) (raw)
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Chemistry of Materials, 2004
Solution combustion synthesis of different oxides involves a self-sustained reaction between an oxidizer (e.g., metal nitrate) and a fuel (e.g., glycine, hydrazine). The mechanism of synthesis for three major iron oxide phases, i.e., R-and γ-Fe 2 O 3 and Fe 3 O 4 , using the combustion approach and a combination of simple precursors such as iron nitrate and oxalate, as well as different fuels, is investigated. Based on the obtained fundamental knowledge, for the first time in the literature, the above powders with well-crystalline structures and surface areas in the range 50-175 m 2 /g are produced using a single approach while simultaneously avoiding additional calcination procedures. It is also shown that utilizing complex fuels and complex oxidizers is an attractive methodology to control the product composition and properties.
1997
Highly dispersed -Fe 2 O 3 powders with particle sizes down to 5 nm were directly synthesized by combustion of solutions of iron pentacarbonyl or iron(III) acetylacetonate in toluene in an oxyhydrogen flame. The particle size as well as other properties of the obtained powders can be controlled simply by varying the iron concentration in the starting solutions. Phase composition, morphological and magnetic properties of the powders were studied. The reasons for the formation of -Fe 2 O 3 are discussed by means of structure-chemical/kinetic considerations. The materials are interesting as recording materials, or ferrofluids, or for colour imaging and bioprocessing.
Physical properties of α-Fe2O3 nanoparticles fabricated by modified hydrolysis technique
Applied Nanoscience, 2013
We have tested modified hydrolysis method for the preparation of a-Fe 2 O 3 nanoparticles. The particles after synthesis were applied for a series of physicochemical techniques. Iron chloride was used as a precursor material. The particle size distribution was determined using zeta sizer and scanning electron microscopy. The surface area and the morphology of the particles vary by changing the concentration of the precursor material. The size of nanoparticles varies from 10 to 90 nm. The particles having size of 23 ± 1 nm were separated out from the solution and their size remains almost the same even after one month. Energy dispersive X-ray analysis (EDX) of Fe 2 O 3 nanoparticles confirms the purity of the desired material. The weight loss of the particles with respect to the temperature was studied by thermogravimetric and differential thermogravimetric (TG/DTG) analysis. X-ray diffraction (XRD) has been employed to study the crystallinity of the particles.
Journal of Materials Science, 2007
This article describes the solution combustion synthesis technique as applicable to iron oxide powder production using urea as fuel and ferric nitrate as an oxidizer. It focuses on the thermodynamic modeling of the combustion reaction under different fuel-to-oxidant ratios. X-ray diffraction showed magnetite (Fe3O4) and hematite (α-Fe2O3) phase formations for the as-synthesized powders. The smallest crystallite size was obtained by stoichiometric chemical reaction. The magnetic properties of the samples are also carefully discussed as superparamagnetic behavior.
Journal of Nanoscience and Nanotechnology, 2006
Nanoparticles of iron(III) oxide were synthesized by spontaneous combustion of ferrocene in ethanol solution using a simple spirit lamp. X-ray powder diffraction and electron diffraction analysis of the powder suggested the formation of -Fe 2 O 3 (Maghemite phase) having lattice constant 8 3539 ± 0 0209 Å. Transmission Electron Micrograph suggested the formation of spherical particles with an average diameter of 24 7 ± 1 6 nm. A sextet with an isomeric shift of 0.328 mm s −1 seen in the Mossbauer spectrum recorded at room temperature, further supports the formation of -Fe 2 O 3 . The particles were dispersed freely in the polar solvents like ethanol, dimethyl sulfoxide, and water. Infra Red spectrum gave bands at 400, 432, 565, and 638 cm −1 , which confirms the presence of -Fe 2 O 3 phase.
Journal of Materials Science, 2007
This article describes the solution combustion synthesis technique as applicable to iron oxide powder production using urea as fuel and ferric nitrate as an oxidizer. It focuses on the thermodynamic modeling of the combustion reaction under different fuel-to-oxidant ratios. X-ray diffraction showed magnetite (Fe 3 O 4 ) and hematite (a-Fe 2 O 3 ) phase formations for the as-synthesized powders. The smallest crystallite size was obtained by stoichiometric chemical reaction. The magnetic properties of the samples are also carefully discussed as superparamagnetic behavior.
Auto-Combustion Synthesis of Nanocrystalline FeCrO3
2011 International Conference on Nanoscience, Technology and Societal Implications, 2011
Nanocrystalline FeCrO 3 with particle size of about 83-123 nm was directly synthesized by sol-gel autocombustion method at room temperature. The overall process involves three steps: formation of homogeneous sol; formation of dried gel; and combustion of the dried gel. Experiments revealed that FeCrO 3 dried gel derived from glycine and nitrate sol exhibits self-propagating combustion at room temperature once it is ignited in air. After autocombustion, the desired nanocrystalline FeCrO 3 was acquired and no further calcination was needed. The autocombustion was considered as a heat-induced exothermic oxidation-reduction reaction between nitrate ions and carboxyl group. The synthesized powder was characterized by X-ray diffraction (XRD), thermogravimetric and differential thermal analysis (TG/DTA), IR spectroscopy, scanning electron microscopy (SEM) and transmission electron microscopy (TEM).
Combustion Derived Ultrafine γ-Fe 2 O 3 Structure, morphology and thermal studies
Journal of Thermal Analysis and Calorimetry, 2003
A novel combustion method of employing poly(ethylene glycol) with the precursor in a fixed ratio for the synthesis of ultrafine γ-Fe2O3 through a self-propagating combustion synthesis is reported. Four different precursors viz. ferrous hydroxide, ferrous oxalate dihydrate, ferric 8-hydroxyquinoline and ferric acetylacetonate are employed in this study for the conversion of these precursors to ultrafine g-Fe2O3 particles. The as synthesized γ-Fe2O3 samples are characterized by XRD, SEM and thermal techniques. A case study for the synthesis of γ-Fe2O3 employing ferric acetyl acetonate as precursor is reported. The importance of employing thermal analysis techniques in understanding the combustion synthesis is envisaged.
A Facile Method for Synthesis of α-Fe2O3 Nanoparticles and Assessment of Their Characterization
Nature, Environment and Pollution Technology/Nature, environment and pollution technology, 2024
Recently, magnetic nanomaterials have gained much attention from researchers because of their various unique physical and chemical properties and usage in a wide range of technological aspects. In this study, the synthesis of α-Fe 2 O 3 nanoparticles was performed by a simple co-precipitation method. The synthesis of α-Fe 2 O 3 nanoparticles was carried out by mixing ferric nitrate and oxalic acid in an aqueous solution followed by evaporation, resulting in the solution's dried form. The synthesized nanoparticles were analyzed by XRD, FTIR, Raman spectra, SEM-EDX, DSC, BET, and Zeta potential for detailed examination of the morphology, structure, and other physicochemical characteristics. The XRD results confirmed that the nanoparticles formed were Hematite (α-Fe 2 O 3) after the evaluation of obtained spectra compared to the Joint Committee on Powder Diffraction Standards Database (JCPDS). The FTIR spectra showed various bonds among functional groups, O-H bending, Fe-O group, and within-vibration bonds. The phase study of the α-Fe 2 O 3 nanoparticles was performed by using Raman spectroscopy. SEM depicted a sphere-like or rhombohedral (hexagonal) structure, and the EDX spectrum confirmed the peaks of iron and oxygen.
A novel approach for producing α- and γ-Fe 2O 3 nanoparticles in various media
International Journal of Nanoparticles, 2012
Iron (III) chloride hexahydrate (FeCl 3 .6H 2 O), glycerine, three surfactants and sodium hydroxide (NaOH) are used as the precursors for the preparation of α and γ iron oxide nanoparticles. XRD and TEM are employed to characterise the particles. Novel pathways are identified that may be used to produce either α or γ phases without changing the temperature and through changing the preparation sequence. If the as-prepared particles from the solution produced in the presence of a surfactant, are first washed and then calcinated, the α phase is obtained, whereas if the particles are first calcinated and then washed, the γ phase is produced.