Evolution of microstructure and magnetic properties from amorphous Fe3O4/SiO2 nanocomposite

Ghosh, Anamika; Srinivas, V.; Kavita, S.; Ramaprabhu, Sundara

doi:10.1016/j.jmmm.2022.169687

Cited by 5 publications

(4 citation statements)

References 46 publications

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“…g values of ∼1.97–2.03 occur due to the introduction of mobile oxygen centers in Fe 2 O 3 -ECNT-1. High asymmetry signifies the change in Fe 3+ interactions, due to the presence of oxygen vacancies. , Furthermore, the EPR spectrum of Pt 3 Fe-ECNT with comparatively low intensity and symmetric line width substantiates that most of the oxygen vacancies are annihilated during alloying with Pt. XRD patterns of Fe 2 O 3 -ECNT-2, Fe 2 O 3 -ECNT-3, Pt 3 Fe-ECNT-2, and Pt 3 Fe-ECNT-3 are shown in Figure S3a in the Supporting Information for comparative study, which indicates, with the increase in the Fe 2 O 3 content (Figure S3b in the Supporting Information), the Fe atom does not occupy only the Pt lattice sites.…”

Section: Resultsmentioning

confidence: 81%

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Low-Temperature Synthesized Pt₃Fe Alloy Nanoparticles on Etched Carbon Nanotubes Catalyst Support Using Oxygen-Deficient Fe₂O₃ as a Catalytic Center for PEMFC Applications

Ganguly

Ramanujam

Ramaprabhu

2023

ACS Sustainable Chem. Eng.

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Proton exchange membrane fuel cells (PEMFCs) have emerged as one of the most promising next-generation renewable energy technologies for the future. However, for the commercialization of PEMFC, low loading of Pt-based catalysts with suitable catalyst support is the utmost necessity. Pt alloys are useful for achieving good electrochemical activity with low Pt loading. But, high-temperature synthesis of these alloys leads to lower cyclic stability. Herein, we have synthesized Pt3Fe alloy on etched carbon nanotubes at low-temperature using oxygen-deficient Fe2O3-ECNT. This low-temperature synthesized Pt3Fe-ECNT shows excellent electrocatalytic activity due to the change in the d-band center and lattice contraction in the bimetallic alloy system. Lower hydrogen binding energy, increases in the electrochemical surface area (84 ± 3 m2 g–1) and mass activity (0.45 A mgPt –1) of the Pt3Fe-ECNT catalyst, compared to commercial Pt/C (0.36 A mgPt –1), confirms it to be a better catalyst for PEMFC. Furthermore, single-cell studies also show promising performance under real PEMFC conditions. A maximum power density of 530 mW cm–2 at 60 °C is achieved with Pt loading far lower than the U.S. Department of Energy (DOE) 2020 target (0.125 mgPt cm–2) with an excellent Pt catalyst utilization and fast kinetics. After an accelerated durability test of 10 000 cycles, stability studies substantiate it as a suitable catalyst for PEMFC applications.

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Section: Resultsmentioning

confidence: 81%

“…g values of ∼1.97−2.03 occur due to the introduction of mobile oxygen centers in Fe 2 O 3 -ECNT-1. High asymmetry signifies the change in Fe 3+ interactions, due to the presence of oxygen vacancies 32,…”

mentioning

confidence: 99%

Low-Temperature Synthesized Pt₃Fe Alloy Nanoparticles on Etched Carbon Nanotubes Catalyst Support Using Oxygen-Deficient Fe₂O₃ as a Catalytic Center for PEMFC Applications

Ganguly

Ramanujam

Ramaprabhu

2023

ACS Sustainable Chem. Eng.

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“…The more Fe 3 O 4 formed, the more the value of M s increased. [ 39,79 ] Actually, the M s value of MBG‐2 was elevated by 19.6% versus that of initial M‐BaM, yet the M s value of BG was increased by only 8.5% versus that of initial BaM. The appearance of Fe 3 O 4 would be helpful to increase the M s value of MBG more obviously due to the mesoporous structure present in M‐BaM.…”

Section: Resultsmentioning

confidence: 99%

The Ordered Mesoporous Barium Ferrite Compounded with Nitrogen‐Doped Reduced Graphene Oxide for Microwave Absorption Materials

Zhao

Cao

et al. 2023

Small

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Nanocomposites with hierarchical pore structure hold great potentials for applications in the field of microwave‐absorbing materials because of their lightweight and high‐efficiency absorption properties. Herein, M‐type barium ferrite (BaM) with ordered mesoporous structure (M‐BaM) is prepared via a sol–gel process enhanced by mixed anionic and cationic surfactants. The surface area of M‐BaM is enhanced almost ten times compared with BaM together with 40% reflection loss enhancing. Then M‐BaM compounded with nitrogen‐doped reduced graphene oxide (MBG) is synthesized via hydrothermal reaction in which the reduction and nitrogen doping of graphene oxide (GO) in situ occur simultaneously. Interestingly, the mesoporous structure is able to provide opportunity for reductant to enter the bulk M‐BaM reducing its Fe3+ to Fe2+ and further forms Fe3O4. It requires an optimal balance among the remained mesopores in MBG, formed Fe3O4, and CN in nitrogen‐doped graphene (N‐RGO) for optimizing impedance matching and greatly increasing multiple reflections/interfacial polarization. MBG‐2 (GO:M‐BaM = 1:10) achieves the minimum reflection loss of −62.6 dB with an effective bandwidth of 4.2 GHz at an ultra‐thin thickness of 1.4 mm. In addition, the marriage of mesoporous structure of M‐BaM and light mass of graphene reduces the density of MBG.

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“…The image revealed that most of the particles were agglomerated, which might be due to the thickening properties of A. cepa or the presence of hydroxyl groups from the extract [41]. Besides, the tendency of agglomeration is not surprising as the synthesized Fe3O4-NPs are small in size and possess magnetic characteristics [42].…”

Section: Characterizationmentioning

confidence: 98%

Biosynthesis of Fe3O4 Nanoparticles mediated Allium cepa extract: Chemical characterization and antimicrobial applications

K.,

Qasim,

Abbas

et al. 2023

Preprint

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Scientists have become more interested in the use of plant extracts as efficient capping and reducing agents for the environmentally friendly fabrication of nanoparticles. In the current study, the Iraqi onion extract (Allium cepa) was prepared and subsequently used as a reducing agent for the biosynthesis of Fe3O4 nanoparticles. UV-visible, FT-IR, XRD, TEM, FESEM, and EDS investigations were used to characterize nanoparticles. The in vitro cytotoxicity of both A. cepa extract and Fe3O4 NPs was evaluated in MDCK-SIAT cells using the MTT test, and the antiviral activity of Fe3O4 NPs was investigated using the Neuraminidase Assay Kit MAK12. The antibacterial activities of A. cepa extract and Fe3O4 NPs were investigated against S. aureus, and E. coli using a disk-diffusion approach. Our results showed the generation of stable, crystalline, and semi-spherical, 36 ± 1.23 nm-sized Fe3O4 nanoparticles, and had strong antibacterial, and antiviral activities, assuming that onion peel extract is an excellent choice for producing Fe3O4 nanoparticles, which may be utilized in the future for a range of therapeutic objectives.

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Evolution of microstructure and magnetic properties from amorphous Fe3O4/SiO2 nanocomposite

Cited by 5 publications

References 46 publications

Low-Temperature Synthesized Pt₃Fe Alloy Nanoparticles on Etched Carbon Nanotubes Catalyst Support Using Oxygen-Deficient Fe₂O₃ as a Catalytic Center for PEMFC Applications

Low-Temperature Synthesized Pt₃Fe Alloy Nanoparticles on Etched Carbon Nanotubes Catalyst Support Using Oxygen-Deficient Fe₂O₃ as a Catalytic Center for PEMFC Applications

The Ordered Mesoporous Barium Ferrite Compounded with Nitrogen‐Doped Reduced Graphene Oxide for Microwave Absorption Materials

Biosynthesis of Fe3O4 Nanoparticles mediated Allium cepa extract: Chemical characterization and antimicrobial applications

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Evolution of microstructure and magnetic properties from amorphous Fe3O4/SiO2 nanocomposite

Cited by 5 publications

References 46 publications

Low-Temperature Synthesized Pt3Fe Alloy Nanoparticles on Etched Carbon Nanotubes Catalyst Support Using Oxygen-Deficient Fe2O3 as a Catalytic Center for PEMFC Applications

Low-Temperature Synthesized Pt3Fe Alloy Nanoparticles on Etched Carbon Nanotubes Catalyst Support Using Oxygen-Deficient Fe2O3 as a Catalytic Center for PEMFC Applications

The Ordered Mesoporous Barium Ferrite Compounded with Nitrogen‐Doped Reduced Graphene Oxide for Microwave Absorption Materials

Biosynthesis of Fe3O4 Nanoparticles mediated Allium cepa extract: Chemical characterization and antimicrobial applications

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Low-Temperature Synthesized Pt₃Fe Alloy Nanoparticles on Etched Carbon Nanotubes Catalyst Support Using Oxygen-Deficient Fe₂O₃ as a Catalytic Center for PEMFC Applications

Low-Temperature Synthesized Pt₃Fe Alloy Nanoparticles on Etched Carbon Nanotubes Catalyst Support Using Oxygen-Deficient Fe₂O₃ as a Catalytic Center for PEMFC Applications