Synthesis of Highly Magnetic Iron Carbide Nanoparticles via a Biopolymer Route

Schnepp, Zoë; Wimbush, Stuart C.; Antonietti, Markus; Giordano, Cristina

doi:10.1021/cm101746z

Cited by 125 publications

(100 citation statements)

References 19 publications

(21 reference statements)

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“…The cementite was prepared by decomposition of a mixture of iron(III) acetate and gelatin at 700 °C. [9] The nanoparticles of Hägg carbide, Fe5C2, were prepared by decomposition of iron pentacarbonyl in the presence of hexadecyltrimethylammonium bromide (CTAB) at 350 °C. [10] The details of the synthesis procedures may be found in the relevant sources provided.…”

Section: Methodologiesmentioning

confidence: 99%

Variable Temperature 57Fe-Mössbauer Spectroscopy Study of Nanoparticle Iron Carbides

Scrimshire¹,

Lobera²,

Kultyshev³

et al. 2015

Croat. Chem. Acta

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Near-phase-pure nanoparticle iron carbides (Fe3C and Fe5C2) were synthesised. Debye model calculations were used with hyperfine parameters gathered by 57 Fe Mössbauer spectroscopy within a temperature range of 10 K to 293 K, with analysis providing Debye temperatures of 422 K and 364 K for two Fe sites in Fe5C2 and 355 K for ferromagnetic Fe3C. The intrinsic isomer shifts were calculated as 0.45 mm s −1 and 0.43 mm s −1 for iron sites 1 and 2 respectively in Fe5C2 and 0.42 mm s −1 for Fe3C. Recoil-free fractions for the two iron sites were also calculated at f300 0.785 and 0.726 for site 1 and 2 respectively.

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Section: Methodologiesmentioning

confidence: 99%

Variable Temperature 57Fe-Mössbauer Spectroscopy Study of Nanoparticle Iron Carbides

Scrimshire¹,

Lobera²,

Kultyshev³

et al. 2015

Croat. Chem. Acta

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“…In this system, addition of the Ti-acetylacetone precursor to alginate considerably increased the viscosity, showing cross-linking of the biopolymer by the Ti cation. This templating effect has been shown many times to constrain the nucleation and growth of crystalline materials in the sol-gel synthesis of metal-oxide and carbide nanostructures [25][26][27]. For samples containing 10 or 25 mol% W, the ternary Ti x W 1−x N phase begins to emerge at 800…”

Section: Resultsmentioning

confidence: 99%

“…Alginate is the structural component of many types of seaweed and comprises a carboxylate-functionalized polysaccharide, which is strongly cross-linked by metal cations in water. This metal-binding ability has been shown to make alginate an effective template for synthesizing nanostructures of metal oxides and carbides [25][26][27]. Electron microscopy and scanning energy-dispersive x-ray analysis revealed that the synthesized oxide and nitride particles are highly interspersed.…”

Section: Introductionmentioning

confidence: 99%

One-step route to a hybrid TiO₂/Ti_xW_1−xN nanocomposite byin situselective carbothermal nitridation

Schnepp

Hollamby

Tanaka

et al. 2012

Science and Technology of Advanced Materials

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Metal oxide/nitride nanocomposites have many existing and potential applications, e.g. in energy conversion or ammonia synthesis. Here, a hybrid oxide/nitride nanocomposite (anatase/Ti x W 1−x N) was synthesized by an ammonia-free sol-gel route. Synchrotron x-ray diffraction, complemented with electron microscopy and thermogravimetric analysis, was used to study the structure, composition and mechanism of formation of the nanocomposite. The nanocomposite contained nanoparticles (<5 nm diameter) of two highly intermixed phases. This was found to arise from controlled nucleation and growth of a single oxide intermediate from the gel precursor, followed by phase separation and in situ selective carbothermal nitridation. Depending on the preparation conditions, the composition varied from anatase/Ti x W 1−x N at low W content to an isostructural mixture of Ti-rich and W-rich Ti x W 1−x N at high W content. In situ selective carbothermal nitridation offers a facile route to the synthesis of nitride-oxide nanocomposites. This conceptually new approach is a significant advance from previous methods, which generally require ammonolysis of a pre-synthesized oxide.

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“…It should be noted that the Fe 3 C particle size in these systems is still much smaller than in the sol-gel synthesis of single-phase Fe 3 C from gelatin. 16 The flexible nature of this method is demonstrated in the synthesis of TiO 2 / Fe 3 N (Fig. S13, ESI †).…”

mentioning

confidence: 99%

“…Recently, we have shown that abundant biopolymers such as alginate are effective precursors for synthesis of oxide, 14 nitride 15 or carbide 16 nanostructures. Biopolymers are particularly suited to control of particle size in ceramics due to their ability to bind strongly to metal cations.…”

mentioning

confidence: 99%

A family of oxide–carbide–carbon and oxide–nitride–carbon nanocomposites

Schnepp¹,

Hollamby²,

Tanaka³

et al. 2014

Chem. Commun.

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This paper describes a powerful and versatile approach that combines the benefits of sol-gel processing with controlled phase separation to yield oxide-carbide-carbon or oxide-nitride-carbon nanocomposites.Transition metal carbides and nitrides are valuable materials for applications such as fuel cell electrocatalysis, 1 ammonia synthesis 2 and photocatalytic water splitting. 3 In these systems, the properties often depend on control of particle size, morphology and accessible surface area. 4 Sol-gel, 5 solvothermal 6 and templating 7 processes have all been used to generate carbides and nitrides with small particle size or porosity. A major hurdle that remains is the controlled and tunable synthesis of composites, particularly carbides or nitrides combined with metal oxides. 8 Such architectures are critical for applications such as noble metal-replacement in solar water splitting. 9 Combining two different ceramics in a nanocomposite presents a significant synthetic challenge. Historically, it has been achieved simply by mechanical mixing, which can seriously compromise the properties of one or both components. More effective methods use ammonolysis 10,11 or temperature programmed reduction 12 of oxide-oxide nanocomposites but have the disadvantage of using hazardous synthesis gases, or multi-step processes. Pinpointing more efficient and sustainable synthesis routes is critical to future materials design. 13 On this basis, a generalised one-pot sol-gel method to composites of two or more ceramic materials would have the key advantages of: (i) a single heating step, (ii) fine-tuning of particle size while achieving good interspersion and (iii) standard, inexpensive and non-hazardous synthesis atmospheres such as nitrogen.Recently, we have shown that abundant biopolymers such as alginate are effective precursors for synthesis of oxide, 14 nitride 15 or carbide 16 nanostructures. Biopolymers are particularly suited to control of particle size in ceramics due to their ability to bind strongly to metal cations. 17 Remarkably, it is also possible to force oxide/carbide or oxide/nitride phase separation from these homogeneous precursors by exploiting differences in stability of intermediate oxides. 18 So far, however, full separation was only achieved in one system (Fe 3 C-MgO). 19 In this paper, we demonstrate the versatility of the sol-gel route in the synthesis of a family of nanocomposites. This new general route emphasizes the potential of sol-gel methods for synthesis of multifunctional materials.Nanocomposites of TiO 2 -Fe 3 C, TiO 2 -WN, CeO 2 -Fe 3 C, CeO 2 -WN, MgO-Fe 3 C and MgO-WN were synthesized by mixing aqueous (or ethanolic) metal salts with hot gelatin solution, stirring vigorously and then drying at 80 1C. The resulting sponge-like precursors were calcined under nitrogen. Samples are denoted TF, TW, CF, CW, MF and MW. A range of molar ratios (100 : 0, 75 : 25, 50 : 50 and 0 : 100) were prepared for each sample and labelled 0, 25, 50 and 100 respectively. For example, sample TF25 was prepared with ...

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Synthesis of Highly Magnetic Iron Carbide Nanoparticles via a Biopolymer Route

Cited by 125 publications

References 19 publications

Variable Temperature 57Fe-Mössbauer Spectroscopy Study of Nanoparticle Iron Carbides

Variable Temperature 57Fe-Mössbauer Spectroscopy Study of Nanoparticle Iron Carbides

One-step route to a hybrid TiO₂/Ti_xW_1−xN nanocomposite byin situselective carbothermal nitridation

A family of oxide–carbide–carbon and oxide–nitride–carbon nanocomposites

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Synthesis of Highly Magnetic Iron Carbide Nanoparticles via a Biopolymer Route

Cited by 125 publications

References 19 publications

Variable Temperature 57Fe-Mössbauer Spectroscopy Study of Nanoparticle Iron Carbides

Variable Temperature 57Fe-Mössbauer Spectroscopy Study of Nanoparticle Iron Carbides

One-step route to a hybrid TiO2/TixW1−xN nanocomposite byin situselective carbothermal nitridation

A family of oxide–carbide–carbon and oxide–nitride–carbon nanocomposites

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One-step route to a hybrid TiO₂/Ti_xW_1−xN nanocomposite byin situselective carbothermal nitridation