Detailed Mössbauer study of the cation distribution in CoFe2O4 ferrites

Rusanov, V.; Gushterov, V.; Nikolov, S.; Trautwein, A. X.

doi:10.1007/978-3-642-01370-6_52

Cited by 4 publications

(2 citation statements)

References 9 publications

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“…However, the appearance of hematite as a secondary phase was 10 observed for all utilized thermal conditions. The ferrites synthesized via this method present a rather low inversion degree, unlike the normal behavior of the bulk material.…”

Section: Discussionmentioning

confidence: 74%

“…[9] Its large magnetocrystalline anisotropy and facile synthesis, coupled to the aforementioned features of ferrites, make this material an ideal candidate for cutting-edge applications in industry. [10] Under ambient conditions, most ferrites crystallize in the spinel space group ( ̅ , n°227). This family of compounds presents the formulation A 2+ B 3+ 2 O 2-4 , with the anions arranged in an fcc structure, whilst the divalent and trivalent cations occupy 1/8 of the tetrahedral and half of the octahedral sites, respectively.…”

Section: Introductionmentioning

confidence: 99%

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Effect of the thermal treatment on the magnetic and structural properties of cobalt ferrite particles

Venturini

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Cunha

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Ceramics International

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Section: Discussionmentioning

confidence: 74%

Section: Introductionmentioning

confidence: 99%

Effect of the thermal treatment on the magnetic and structural properties of cobalt ferrite particles

Venturini

Piva

Cunha

et al. 2016

Ceramics International

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Significance of Engineering the Octahedral Units to Promote the Oxygen Evolution Reaction of Spinel Oxides

et al. 2019

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electrolyzer are oxygen evolution reaction (OER) and hydrogen evolution reaction (HER), respectively. The OER at the anode, proceeding through 4e − transfer and generates more than one intermediates, is much more kinetically sluggish than the 2e − transfer HER. [1] Lowering the energy barrier of OER is the key to the enhancement of overall water splitting efficiency. The state-of-the-art OER electrocatalysts, such as iridium-and ruthenium-based materials, are not sustainable choices due to the high cost and element scarcity. Transition metal (TM) oxides, with wide variety of physical and electronic properties, are considered as promising low-cost alternatives. [2] Spinel-type oxides have been extensively investigated as OER electrocatalysts and have presented outstanding catalytic performances. [2b,3] The crystal structure of spinel is made up of oxygen anions arranged in a cubic close-packed lattice with metallic ions filling the tetrahedral and octahedral interstices. Of all the 96 interstices between the oxygen anions in one cubic unit cell, 64 are four oxygencoordinated tetrahedral sites and 32 are six oxygen-coordinated octahedral sites. In the spinel lattice, only half of the octahedral interstices and one-eighth of the tetrahedral interstices are filled with metal cations. The remaining unoccupied interstitial sites make spinel a very open structure to accommodate the migration of cations. [4] For binary spinel AB 2 O 4 , the distribution of The clean energy carrier, hydrogen, if efficiently produced by water electrolysis using renewable energy input, would revolutionize the energy landscape. It is the sluggish oxygen evolution reaction (OER) at the anode of water electrolyzer that limits the overall efficiency. The large spinel oxide family is widely studied due to their low cost and promising OER activity. As the distribution of transition metal (TM) cations in octahedral and tetrahedral site is an important variable controlling the electronic structure of spinel oxides, the TM geometric effect on OER is discussed. The dominant role of octahedral sites is found experimentally and explained by computational studies. The redox-active TM locating at octahedral site guarantees an effective interaction with the oxygen at OER conditions. In addition, the adjacent octahedral centers in spinel act cooperatively in promoting the fast OER kinetics. In remarkable contrast, the isolated tetrahedral TM centers in spinel prohibit the OER mediated by dual-metal sites. Furthermore, various spinel oxides preferentially expose octahedral-occupied cations on the surface, making the octahedral cations easily accessible to the reactants. The future perspectives and challenges in advancing fundamental understanding and developing robust spinel catalysts are discussed.

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Correlating cation distribution with the structural and magnetic properties of Co0.5Zn0.5AlxFe2–xO4 nanoferrites

Wahba

Mohamed

2020

Appl. Phys. A

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Detailed Mössbauer study of the cation distribution in CoFe2O4 ferrites

Cited by 4 publications

References 9 publications

Effect of the thermal treatment on the magnetic and structural properties of cobalt ferrite particles

Effect of the thermal treatment on the magnetic and structural properties of cobalt ferrite particles

Significance of Engineering the Octahedral Units to Promote the Oxygen Evolution Reaction of Spinel Oxides

Correlating cation distribution with the structural and magnetic properties of Co0.5Zn0.5AlxFe2–xO4 nanoferrites

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