Influence of Cr substitution on Debye-Waller factor and related structural parameters of ZnFe2-xCrxO4 spinels

Khalaf, Kadhim A.M.; Rawas, A.; Gismelssed, A.M.; Al-Jamel, A.; Ani, Salwan K.J. Al; Shongwe, Musa S.; Riyami, K.O. Al; Alawi, S.R. Al

doi:10.1016/j.jallcom.2017.01.083

Cited by 15 publications

(7 citation statements)

References 28 publications

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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%

“…This feature was also reported in previous studies about the crystal structures of ZnFe 2−x Cr x O 4 and was attributed to lattice dimension contraction resulting from the smaller radius of Cr 3+ 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 on the same order of magnitude (Figure S2f).…”

Section: ■ Introductionmentioning

confidence: 99%

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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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Section: Introductionmentioning

confidence: 99%

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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“…52-0277, JCPDS card no. 08-0234 [41][42][43]. The XRD data confirms the formation of a single-phase Ho 3+ substituted NZC ferrite without any unreacted compound or additional phase in the synthesized samples.…”

Section: Xrd Analysismentioning

confidence: 52%

Investigation of structural, electrical, and magnetic variations of Ni-Zn-Co ferrites by substituting rare earth Ho³⁺ for high-frequency applications

Routray,

Saha

2024

Phys. Scr.

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The investigation of structural, magnetic, and electrical properties of Ni0.6Zn0.3Co0.1HoxFe2-xO4 (NZCHF, 0 ≤ x ≤ 0.2) ferrites, synthesized through the sol-gel autocombustion method, has been undertaken. The refined X-ray diffraction (XRD) analysis was performed for XRD data analysis using Fullprof Suite software and it confirmed a single-phase cubic spinel structure, with the determination of crystallite size, refinement parameters and lattice constants. The bulk density of the samples consistently remained lower than the x-ray density, with densities increasing proportionally to the enhancement of Ho concentration. FTIR analysis corroborated the presence of metal-oxygen bonds within the ferrite possessing a spinel cubic structure. 57Fe Mossbauer spectroscopy showed that the hyperfine magnetic field of tetrahedral (A) and octahedral (B) sites decreased with the substitution of Ho3+ ions that preferentially occupy the B site. The impedance analyzer and vibrating sample magnetometer (VSM) were utilized to measure the real and imaginary parts of the complex permeability and magnetic properties of the samples, respectively. Complex impedance plots were scrutinized to discern the contributions of grain and grain boundary resistances, providing insights into the electrical behavior of the ferrite samples. Furthermore, the introduction of Ho concentration led to alterations in other key properties of the ferrites, including coercivity (Hc), retentivity (Mr), anisotropy constant (K), and magnetic moment (μ_B).The impact of the rare-earth content on the magnetic features of the prepared NiZnCo ferrite microspheres was investigated by analyzing magnetic-hysteresis (M-H) loops, which showed soft ferrimagnetism. Concurrently, the dielectric constant and dielectric loss tangent of the studied samples exhibited a decrease with the rise in Ho3+ concentration. The expected reduction in tan loss in the prepared samples is attributed to the increase in ac resistivity associated with the higher Ho3+ content.

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“…Specifically, the (220) crystal plane is more sensitive to cations in tetrahedral sites, while the (440) crystal plane is more sensitive to cations in the tetrahedral sites as well as octahedral sites. [ 32 ] Based on Equation (), which provides a possible in situ solid‐state reaction during the deposition process, it is speculated that this phenomenon is due to the random substitution of Al and Mo atoms for octahedral cation positions increasing with deposition time

\begin{equation}{\mathrm{Fe}}\,{\mathrm{ + }}\,{\mathrm{MoO}}_{\mathrm{3}}\,{\mathrm{ + }}\,{\mathrm{Al}}_{\mathrm{2}}{{\mathrm{O}}}_{\mathrm{3}}\, \to \,{\mathrm{Fe}}{\left( {{\mathrm{Fe,Mo,Al}}} \right)}_{\mathrm{2}}{{\mathrm{O}}}_{\mathrm{4}}\end{equation}

…”

Section: Resultsmentioning

confidence: 99%

“…Specifically, the (220) crystal plane is more sensitive to cations in tetrahedral sites, while the (440) crystal plane is more sensitive to cations in the tetrahedral sites as well as octahedral sites. [32] Based on Equation (1), which provides a possible in situ solid-state reaction during the deposition process, it is speculated that this phenomenon is due to the random substitution of Al and Mo atoms for octahedral cation positions increasing with deposition time…”

Section: Resultsmentioning

confidence: 99%

Hybrid Metal/Spinel Oxide Coating with Microcone Arrays to Stimulate a Photothermal‐Augmented Oxygen Evolution Reaction

Chen,

Xu,

Chen

et al. 2023

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To boost the kinetic process of the oxygen evolution reaction (OER), hybrid CoNiFe/Fe(Fe,Mo,Al)2O4 coatings are deposited on pure Ti substrates (namely, CoNiFe/Fe(Fe,Mo,Al)2O4/Ti electrodes). This new coating features a dense inner layer together with an outer layer of microcone arrays (MCAs). The electrochemical surface area of the electrodes is modulated by controlling the geometrical factors of the MCAs. For the OER in 1.0 m KOH, the electrodes require minimum overpotentials of 245 and 333 mV to realize current densities of, respectively, 10 and 100 mA cm−2. Furthermore, the high aspect ratio of the MCAs enables the electrodes to exhibit strong sunlight capture. Under 10 min of simulated 1.0 sun illumination, the electrode's temperature can rise by up to 108.2 °C. The number of active sites and the OER reaction rate of the electrodes are further increased by photoassistance, with only 234 and 296 mV overpotentials, respectively, needed to generate current densities of 10 and 100 mA cm−2 with a Tafel slope as low as 40.9 mV dec−1. Therefore, the application of this composite coating, which exhibits photothermal effects with respect to conventional Ti electrodes, provides an inspiration for further improvement of OER catalytic efficiency.

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Influence of Cr substitution on Debye-Waller factor and related structural parameters of ZnFe2-xCrxO4 spinels

Cited by 15 publications

References 28 publications

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

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

Investigation of structural, electrical, and magnetic variations of Ni-Zn-Co ferrites by substituting rare earth Ho³⁺ for high-frequency applications

Hybrid Metal/Spinel Oxide Coating with Microcone Arrays to Stimulate a Photothermal‐Augmented Oxygen Evolution Reaction

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Influence of Cr substitution on Debye-Waller factor and related structural parameters of ZnFe2-xCrxO4 spinels

Cited by 15 publications

References 28 publications

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

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

Investigation of structural, electrical, and magnetic variations of Ni-Zn-Co ferrites by substituting rare earth Ho3+ for high-frequency applications

Hybrid Metal/Spinel Oxide Coating with Microcone Arrays to Stimulate a Photothermal‐Augmented Oxygen Evolution Reaction

Contact Info

Product

Resources

About

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

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

Investigation of structural, electrical, and magnetic variations of Ni-Zn-Co ferrites by substituting rare earth Ho³⁺ for high-frequency applications