Preferential site occupancy of Ni ions and oxidation state of Fe ions in the YIG crystal structure obtained by sol-gel method

Caland, J.P.; Medrano, C. P. C.; Caytuero, A.; Baggio‐Saitovitch, E.; Litterst, F. J.; Soares, J.M.; Cabrera-Baez, M.; Padrón-Hernández, E.; Marques, Thalles M.F.; Guerra, Y.; Viana, Bartolomeu C.; Santos, Francisco Eroni Paz dos; Peña-Garcia, R.

doi:10.1016/j.jallcom.2020.156657

Cited by 27 publications

(13 citation statements)

References 41 publications

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“…It is already known that these modes are attributable to the displacements of lighter oxygen ions in Fe 3+ polyhedral units in the YIG garnet [35]. Above 400 cm −1 , the stretching of Fe-O bonds in tetrahedral and octahedral sites appeared in all solids [35,37]. These observations implied that the crystalline YIG phase was not affected by running the catalytic tests, since the spectral dependence of Fe or Cr was almost the same as that of the fresh sample [5].…”

Section: Structure By Raman Ftir and Xrd And Valence States By Eprmentioning

confidence: 70%

“…Raman bands at 319 and 370 cm −1 corresponded to the bending of Y and Fe cations in tetrahedral (24d) and dodecahedral units (24c) and vibration oscillations of FeO 4 tetrahedron [34][35][36]. It is already known that these modes are attributable to the displacements of lighter oxygen ions in Fe 3+ polyhedral units in the YIG garnet [35].…”

Section: Structure By Raman Ftir and Xrd And Valence States By Eprmentioning

confidence: 98%

“…The structural features and chemical states of spent yttrium iron garnet ferrites are shown in Figure 4. Raman bands at 319 and 370 cm −1 corresponded to the bending of Y and Fe cations in tetrahedral (24d) and dodecahedral units (24c) and vibration oscillations of FeO4 tetrahedron [34][35][36]. It is already known that these modes are attributable to the displacements of lighter oxygen ions in Fe 3+ polyhedral units in the YIG garnet [35].…”

Section: Structure By Raman Ftir and Xrd And Valence States By Eprmentioning

confidence: 98%

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Cr-Containing Rare-Earth Substituted Yttrium Iron Garnet Ferrites: Catalytic Properties in the Ethylbenzene Oxidation

et al. 2022

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A series of the Cr-containing erbium substituted yttrium iron garnet ferrites (ECYIG) was synthesized with distinct Cr amounts, herein referred to as Y3(Er0.02Fe5Cr1−x)O12, where x refers to Cr amounts from 0 to 0.05. The catalytic performance of the solids was investigated in ethylbenzene oxidation in the presence of hydrogen peroxide to assess the role of Cr and Er present in the YIG garnet lattice for fine chemistry compound production. Raman spectroscopy, HRTEM, EPR and FTIR revealed that the insertion of Er (at a fixed amount of 2%) in dodecahedral sites had a great impact on the catalytic activity of the garnets. Both Er3+ and Y3+ in the lattice simultaneously provided structural stability to the garnet structure in any harsh environment. XPS and EPR indicated that the Cr3+ ions replaced those of Fe3+ located in both octahedral and tetrahedral sites of the YIG garnets. The Cr3+ ions acted as electronic promoter to increase the oxidation rate of the Fe3+ active species responsible for activating the EB molecule. SEM-EDS demonstrated that the solids having Cr amounts lower than 4% experienced the most severe deactivation due to the Cr leaching and strong carbon species adsorption on the surface of the catalysts, which decreased their efficiency in the reaction.

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Section: Structure By Raman Ftir and Xrd And Valence States By Eprmentioning

confidence: 70%

Section: Structure By Raman Ftir and Xrd And Valence States By Eprmentioning

confidence: 98%

Section: Structure By Raman Ftir and Xrd And Valence States By Eprmentioning

confidence: 98%

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Cr-Containing Rare-Earth Substituted Yttrium Iron Garnet Ferrites: Catalytic Properties in the Ethylbenzene Oxidation

et al. 2022

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“…The Cp OxMix released heat during coke re‐oxidation, resulting in high mass loss in TGA‐DTA due to excessive CO 2 formation along with coke in two forms: nanotubes and encapsulated carbon over metallic nickel [71,72] . Refinement Rietveld results pointed to an increase of O 1 occupancy factor in Sol‐gel hydrotalcites providing enrichment of oxygen, and atomic defects on cubic structure of mixed oxide, [73] compared to co‐precipitation and Ion exchange oxide with the same nominal composition of Nickel. TGA‐DTA results with oxygen from figure 6, exhibited that Sg OxMix exhaust has a gain mass, attributed to Ni 0 re‐oxidation with low CO 2 release, in this case the nickel re‐oxidation‐controlled coke deposition from surface oxygenation of nickel cluster metal formed [74] .…”

Section: Resultsmentioning

confidence: 99%

“…The Cp OxMix released heat during coke re-oxidation, resulting in high mass loss in TGA-DTA due to excessive CO 2 formation along with coke in two forms: nanotubes and encapsulated carbon over metallic nickel. [71,72] Refinement Rietveld results pointed to an increase of O 1 occupancy factor in Sol-gel hydrotalcites providing enrichment of oxygen, and atomic defects on cubic structure of mixed oxide, [73] compared…”

Section: Tga-dta Of Spent Catalysts With Oxygen and Analysis Of Coke ...mentioning

confidence: 99%

Enhancing Catalytic Performance with Sol‐Gel Hydrotalcite‐Derived Nickel Oxide Catalysts for Dry Reforming of Methane: An Examination on Reactivity and Coke Formation

Gonzalez Caranton,

Stavale,

Annese

et al. 2023

ChemCatChem

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Hydrotalcite‐based materials are preferred as catalysts due to their versatility and easiness of their synthesis. This work studies supported nickel catalysts made from hydrotalcites through sol‐gel synthesis, Ni‐EDTA impregnation, and coprecipitation. The synthetized hydrotalcites present nanocapsular morphology and dispersed nickel nano‐oxide particles after calcination at 500 °C. The catalysts were evaluated at 600 °C and 800 °C for 8 hours and demonstrated high conversions and varying yields, with sol‐gel oxide catalysts (SgOxMix) showing the best performance with the highest reactivity and controlled coke formation at 800 °C after 14 hours of testing. The mixed oxide morphology promotes electronic effects and inhibits carbon encapsulation of metallic particles. Principal component analysis was performed to explain fluctuations in the reaction pathway.

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Theoretical investigation of cation distribution and their effect on the physical properties of Ni-doped YIG system

Matilla-Arias

Guerra²,

Mariño-Castellanos³

et al. 2022

Appl. Phys. A

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Preferential site occupancy of Ni ions and oxidation state of Fe ions in the YIG crystal structure obtained by sol-gel method

Cited by 27 publications

References 41 publications

Cr-Containing Rare-Earth Substituted Yttrium Iron Garnet Ferrites: Catalytic Properties in the Ethylbenzene Oxidation

Cr-Containing Rare-Earth Substituted Yttrium Iron Garnet Ferrites: Catalytic Properties in the Ethylbenzene Oxidation

Enhancing Catalytic Performance with Sol‐Gel Hydrotalcite‐Derived Nickel Oxide Catalysts for Dry Reforming of Methane: An Examination on Reactivity and Coke Formation

Theoretical investigation of cation distribution and their effect on the physical properties of Ni-doped YIG system

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