Magnetic enhancement of carbon-encapsulated magnetite nanoparticles

Lee, Jiann‐Shing; Song, Yuan-Jhe; Hsu, Hua-Shu; Lin, Chun-Rong; Huang, Jing-Ya; Chen, Jiunn

doi:10.1016/j.jallcom.2019.03.191

Cited by 20 publications

(7 citation statements)

References 40 publications

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“…For the initial sample Fe 3 O 4 @C, M s = 92.8 emu/g which is equal to M s of bulk Fe 3 O 4 samples, 84 emu/g at room temperature [ 14 ], and essential greater than values presented by other authors for Fe 3 O 4 NPs, for example, [ 19 , 21 ]. At the same time, the magnetization increase in the magnetite NPs coated with carbon comparing to uncoated NPs was noted by some authors [ 27 , 28 ]. To explain this enhancement, the authors of Refs.…”

Section: Resultssupporting

confidence: 56%

“…To explain this enhancement, the authors of Refs. [ 27 , 28 ] proposed an ionic hypothesis of a polarized charge transfer to the A-site in the Fe 3 O 4 NPs leading to a charge reduction at the A-site (i.e., Fe A 3+ → Fe A 2+ ). Since the resulting magnetization of the sample in Fe 3 O 4 is due to the difference in the magnetic moments of Fe ions occupying octahedral and tetrahedral positions, the redistribution of Fe ions between oppositely magnetized sublattices in magnetite NPs is caused, for example, by technological conditions and can be one of the reasons for the different values of M s .…”

Section: Resultsmentioning

confidence: 99%

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Carbon Double Coated Fe3O4@C@C Nanoparticles: Morphology Features, Magnetic Properties, Dye Adsorption

et al. 2022

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This work is devoted to the study of magnetic Fe3O4 nanoparticles doubly coated with carbon. First, Fe3O4@C nanoparticles were synthesized by thermal decomposition. Then these synthesized nanoparticles, 20–30 nm in size were processed in a solution of glucose at 200 °C during 12 h, which led to an unexpected phenomenon—the nanoparticles self-assembled into large conglomerates of a regular shape of about 300 nm in size. The morphology and features of the magnetic properties of the obtained hybrid nanoparticles were characterized by transmission electron microscopy, differential thermo-gravimetric analysis, vibrating sample magnetometer, magnetic circular dichroism and Mössbauer spectroscopy. It was shown that the magnetic core of Fe3O4@C nanoparticles was nano-crystalline, corresponding to the Fe3O4 phase. The Fe3O4@C@C nanoparticles presumably contain Fe3O4 phase (80%) with admixture of maghemite (20%), the thickness of the carbon shell in the first case was of about 2–4 nm. The formation of very large nanoparticle conglomerates with a linear size up to 300 nm and of the same regular shape is a remarkable peculiarity of the Fe3O4@C@C nanoparticles. Adsorption of organic dyes from water by the studied nanoparticles was also studied. The best candidates for the removal of dyes were Fe3O4@C@C nanoparticles. The kinetic data showed that the adsorption processes were associated with the pseudo-second order mechanism for cationic dye methylene blue (MB) and anionic dye Congo red (CR). The equilibrium data were more consistent with the Langmuir isotherm and were perfectly described by the Langmuir–Freundlich model.

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Section: Resultssupporting

confidence: 56%

Section: Resultsmentioning

confidence: 99%

Carbon Double Coated Fe3O4@C@C Nanoparticles: Morphology Features, Magnetic Properties, Dye Adsorption

et al. 2022

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“…[ 5–7 ] Indeed, the SWCNT ensures a fine dispersion of magnetic species along the longitudinal axis, thus restricting the magnetic coupling between them and thereby enhancing the inherent properties of nanoparticles. [ 8–11 ] A reduction of intermolecular dipole–dipole interactions between the neighboring encapsulated molecules leading to enhanced magnetic properties was recently demonstrated for single‐molecule magnets. [ 12 ] The 1D arrangement of single‐molecule magnets provides the suppression of quantum tunneling of the magnetization [ 12,13 ] that is crucial for practical applications.…”

Section: Figurementioning

confidence: 99%

Magnetic Properties of 1D Iron–Sulfur Compounds Formed Inside Single‐Walled Carbon Nanotubes

Окотруб

Chernov

Лавров

et al. 2020

Physica Rapid Research Ltrs

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Carbon-encapsulated magnetic nanoparticles are very prospective in the context of biomedical applications, [1] memory devices, [2] and magnetic sensors. [3] Singlewalled carbon nanotubes (SWCNTs) stand out among other different protective materials. They not only serve as a template for nano-dimensional growth [4] and promote interactions between the encapsulated species, but also can influence the properties of the formed host-guest structures. [5-7] Indeed, the SWCNT ensures a fine dispersion of magnetic species along the longitudinal axis, thus restricting the magnetic coupling between them and thereby enhancing the inherent properties of nanoparticles. [8-11] A reduction of intermolecular dipole-dipole interactions between the neighboring encapsulated molecules leading to enhanced magnetic properties was recently demonstrated for single-molecule magnets. [12] The 1D arrangement of singlemolecule magnets provides the suppression of quantum tunneling of the magnetization [12,13] that is crucial for practical applications. Initially, filling of nanotubes with magnetic species was studied for cobalt, [8,14,15] iron, [9,10,16-18] and nickel [19] nanoparticles. These metals are frequently used as catalysts for the growth of nanotubes [20] and often detected as side

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“…Several studies have pointed out the importance of employing a carbon layer since it is (i) practical, (ii) biocompatible, and (iii) would lead to reducing the damage of the magnetic core when exposed to aggressive conditions [17][18][19]. To achieve a proper coating of the magnetic core, a wide range of treatments are available, including chemical vapor deposition, solution plasma processing, hydrothermal methods, spray pyrolysis, and solid-phase synthesis [20][21][22]. It has been demonstrated that IONP encapsulation employing different coatings based on citric acid, lactonic acid, polyvinylpyrrolidone, or polyethylene glycol enhances the chemical, thermal, and colloidal stabilities [23,24].…”

Section: Introductionmentioning

confidence: 99%

Influence of post-pyrolysis treatment on physicochemical properties and acid medium stability of magnetic carbon nanocomposites

Burbano

Medina

Sánchez

et al. 2022

Biomass Conv. Bioref.

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This study presents the preparation of magnetic carbon nanocomposites (MCNCs) through a two-step procedure: (i) in situ co-precipitation of magnetite (Fe3O4) nanoparticles into four different carbonaceous matrixes and (ii) post-pyrolysis treatment to coat the magnetic core. Four post-pyrolysis MCNCs were obtained: MACP (post-pyrolyzed magnetic activated carbon), MCCP (post-pyrolyzed magnetic charcoal), MHCPOR (post-pyrolyzed magnetic hydrochar from orange residue), and MBCPSFH (post-pyrolyzed magnetic biochar from sunflower husk). These four samples were compared with the starting MCNCs prepared without post-pyrolysis treatment: MAC, MCC, MHCOR, and MBCSFH, respectively. After post-pyrolysis treatment, a thin carbon layer surrounding some of the magnetite nanoparticles was identified by transmission electron microscopy. Post-pyrolysis modified the porous structure and chemical composition of MCNCs. Furthermore, a leaching test with acid sulfuric solution at 90 °C was carried out. The results suggested that the MHCPOR and MBCPSFH were more stable in an acidic medium than MACP and MCCP, indicating that the coat generated during post-pyrolysis of hydrochar and biochar could partially protect the magnetic core by reducing Fe leaching into the aqueous solution. Biochar and the hydrochar-based MCNCs before and after post-pyrolysis treatment exhibit superparamagnetic properties; however, their saturation magnetization (Ms) decreased considerably. These results open the potential application fields of MCNCs obtained by post-pyrolysis of biochar and hydrochar-based materials in acidic mediums.

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Magnetic enhancement of carbon-encapsulated magnetite nanoparticles

Cited by 20 publications

References 40 publications

Carbon Double Coated Fe3O4@C@C Nanoparticles: Morphology Features, Magnetic Properties, Dye Adsorption

Carbon Double Coated Fe3O4@C@C Nanoparticles: Morphology Features, Magnetic Properties, Dye Adsorption

Magnetic Properties of 1D Iron–Sulfur Compounds Formed Inside Single‐Walled Carbon Nanotubes

Influence of post-pyrolysis treatment on physicochemical properties and acid medium stability of magnetic carbon nanocomposites

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