Influence of chromium ion substitution on the structure and properties of zinc ferrite synthesized by the sol–gel auto-combustion method

Borhan, Adrian Iulian; Slatineanu, Tamara; Iordan, Alexandra Raluca; Palamaru, Mircea Nicolae

doi:10.1016/j.poly.2013.03.058

Cited by 45 publications

(22 citation statements)

References 28 publications

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“…Laue equation for cubic lattice was used to determine lattice parameter ( a ), defined as [27]:

a = d_{h k l} \sqrt{h^{2} + k^{2} + l^{2}}

where

d_{h k l} = \frac{λ}{2 sin sans-serifθ}

and d is interplanar distance and h , k , l are miller indices. Lattice parameter for CoFe 2 O 4 is in agreement with standard value, whereas lattice parameter of CoFe 2 O 4 /Fe 3 O 4 is close to the value of the seed nanoparticle.…”

Section: Resultsmentioning

confidence: 99%

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RETRACTED: Structural and Magnetic Response in Bimetallic Core/Shell Magnetic Nanoparticles

et al. 2016

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Bimagnetic monodisperse CoFe2O4/Fe3O4 core/shell nanoparticles have been prepared by solution evaporation route. To demonstrate preferential coating of iron oxide onto the surface of ferrite nanoparticles X-ray diffraction (XRD), High resolution transmission electron microscope (HR-TEM) and Raman spectroscopy have been performed. XRD analysis using Rietveld refinement technique confirms single phase nanoparticles with average seed size of about 18 nm and thickness of shell is 3 nm, which corroborates with transmission electron microscopy (TEM) analysis. Low temperature magnetic hysteresis loops showed interesting behavior. We have observed large coercivity 15.8 kOe at T = 5 K, whereas maximum saturation magnetization (125 emu/g) is attained at T = 100 K for CoFe2O4/Fe3O4 core/shell nanoparticles. Saturation magnetization decreases due to structural distortions at the surface of shell below 100 K. Zero field cooled (ZFC) and Field cooled (FC) plots show that synthesized nanoparticles are ferromagnetic till room temperature and it has been noticed that core/shell sample possess high blocking temperature than Cobalt Ferrite. Results indicate that presence of iron oxide shell significantly increases magnetic parameters as compared to the simple cobalt ferrite.

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“…Laue equation for cubic lattice was used to determine lattice parameter ( a ), defined as [27]:

a = d_{h k l} \sqrt{h^{2} + k^{2} + l^{2}}

where

d_{h k l} = \frac{λ}{2 sin sans-serifθ}

Section: Resultsmentioning

confidence: 99%

“…Lattice parameter for CoFe 2 O 4 is in agreement with standard value, whereas lattice parameter of CoFe 2 O 4 /Fe 3 O 4 is close to the value of the seed nanoparticle. This small difference can be attributed to the lattice mismatch between core and shell, which results in the growth of Fe 3 O 4 phase on CoFe 2 O 4 nanoparticles [27,28]. …”

Section: Resultsmentioning

confidence: 99%

RETRACTED: Structural and Magnetic Response in Bimetallic Core/Shell Magnetic Nanoparticles

et al. 2016

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“…The average grain size is slightly larger than the average crystallite size determined by XRD. This shows that every particle is formed by a number of crystallites [19][20][21]. The SEM micrographs of CoGd Fe 2− O 4 ( = 0) are shown in Figure 4.…”

Section: Structures and Grainmentioning

confidence: 92%

The Structural and Magnetic Properties of Gadolinium Doped CoFe₂O₄ Nanoferrites

Lin

et al. 2015

Journal of Nanomaterials

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Gadolinium substituted cobalt ferrite CoGd x Fe 2−x O 4 (x = 0, 0.04, 0.08) powders have been prepared by a sol-gel autocombustion method. XRD results indicate the production of a single cubic phase of ferrites. The lattice parameter increases and the average crystallite size decreases with the substitution of Gd 3+ ions. SEM shows that the ferrite powers are nanoparticles. Room temperature Mössbauer spectra of CoGd x Fe 22−x O 4 are two normal Zeeman-split sextets, which display ferrimagnetic behavior. The saturation magnetization decreases and the coercivity increases by the Gd 3+ ions.

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“…28 cations than Fe 3+ cations in Oh sites. [31][32] The FESEM images of ZnFe 2-x Cr x O 4 in Figure S2 display that the variation of Cr content causes little difference in their morphology. This is supported by the only slight differences between the BET specific surface areas of ZnFe 2-x Cr x O 4 , which are in the same order of magnitude ( Figure S2f).…”

Section: Introductionmentioning

confidence: 99%

Metal–Oxygen Hybridization Determined Activity in Spinel-Based Oxygen Evolution Catalysts: A Case Study of ZnFe_2–xCr_xO₄

Sun

et al. 2018

Chem. Mater.

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A good understanding of the correlation between electronic properties and catalytic performance is vital to the rational design of active oxygen evolution reaction (OER) catalysts. Here, a volcano-shaped correlation between the OER activity and the Cr substitution amount was found for spinel oxides ZnFe 2−x Cr x O 4 (x = 0−2), in which Zn 2+ resides in tetrahedral (Td) sites while Fe 3+ and Cr 3+ occupy octahedral (Oh) sites. Such a relationship probably is because Cr substitution tunes the e g occupancy of Oh-site transition metals (TM Oh ) via the Oh−Oh superexchange effect. Density functional calculations further revealed the hybridization degree between the TM Oh 3d and the O 2p states, and a volcano-shaped trend was also found in the variation of TM Oh 3d-O 2p hybridization with the amount of Cr substitution. The good correlation between the OER activity and the hybridization highlights the important role of metal−oxygen hybridization in determining the OER activity of these spinel oxides.

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Influence of chromium ion substitution on the structure and properties of zinc ferrite synthesized by the sol–gel auto-combustion method

Cited by 45 publications

References 28 publications

RETRACTED: Structural and Magnetic Response in Bimetallic Core/Shell Magnetic Nanoparticles

RETRACTED: Structural and Magnetic Response in Bimetallic Core/Shell Magnetic Nanoparticles

The Structural and Magnetic Properties of Gadolinium Doped CoFe₂O₄ Nanoferrites

Metal–Oxygen Hybridization Determined Activity in Spinel-Based Oxygen Evolution Catalysts: A Case Study of ZnFe_2–xCr_xO₄

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Influence of chromium ion substitution on the structure and properties of zinc ferrite synthesized by the sol–gel auto-combustion method

Cited by 45 publications

References 28 publications

RETRACTED: Structural and Magnetic Response in Bimetallic Core/Shell Magnetic Nanoparticles

RETRACTED: Structural and Magnetic Response in Bimetallic Core/Shell Magnetic Nanoparticles

The Structural and Magnetic Properties of Gadolinium Doped CoFe2O4 Nanoferrites

Metal–Oxygen Hybridization Determined Activity in Spinel-Based Oxygen Evolution Catalysts: A Case Study of ZnFe2–xCrxO4

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Product

Resources

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The Structural and Magnetic Properties of Gadolinium Doped CoFe₂O₄ Nanoferrites

Metal–Oxygen Hybridization Determined Activity in Spinel-Based Oxygen Evolution Catalysts: A Case Study of ZnFe_2–xCr_xO₄