Correlation of reactivity with structural factors in a series of Fe(II) substituted cobalt ferrites
A series of powdered cobalt ferrites, CoxFe3-xO4 with 0.66≤x<1.00 containing different amounts of FeII, were synthesized by a mild procedure, and their Fe and Co site occupancies and structural characteristics were explored using X-ray anomalous scattering and the Rietveld refinement method....
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| Acceso en línea: | http://hdl.handle.net/20.500.12110/paper_00224596_v179_n7_p2237_Sileo |
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todo:paper_00224596_v179_n7_p2237_Sileo2023-10-03T14:32:56Z Correlation of reactivity with structural factors in a series of Fe(II) substituted cobalt ferrites Sileo, E.E. García Rodenas, L. Paiva-Santos, C.O. Stephens, P.W. Morando, P.J. Blesa, M.A. Cobalt ferrites Electron hopping Kinetic dissolution Rietveld method X-ray anomalous scattering Dissolution Iron compounds Molecular structure Reaction kinetics Substitution reactions Synthesis (chemical) X ray scattering Cobalt ferrites Electron hopping Kinetic dissolution Rietveld method X-ray anomalous scattering Cobalt compounds A series of powdered cobalt ferrites, CoxFe3-xO4 with 0.66≤x<1.00 containing different amounts of FeII, were synthesized by a mild procedure, and their Fe and Co site occupancies and structural characteristics were explored using X-ray anomalous scattering and the Rietveld refinement method. The dissolution kinetics, measured in 0.1 M oxalic acid aqueous solution at 70 °C, indicate in all cases the operation of a contracting volume rate law. The specific rates increased with the FeII content following approximately a second-order polynomial expression. This result suggests that the transfer of FeIII controls the dissolution rate, and that the leaching of a first layer of ions CoII and FeII leaves exposed a surface enriched in slower dissolving octahedral FeIII ions. Within this model, inner vicinal lattice FeII accelerates the rate of FeIII transfer via internal electron hopping. A chain mechanism, involving successive electron transfers, fits the data very well. © 2006 Elsevier Inc. All rights reserved. Fil:Sileo, E.E. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. JOUR info:eu-repo/semantics/openAccess http://creativecommons.org/licenses/by/2.5/ar http://hdl.handle.net/20.500.12110/paper_00224596_v179_n7_p2237_Sileo |
| institution |
Universidad de Buenos Aires |
| institution_str |
I-28 |
| repository_str |
R-134 |
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Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) |
| topic |
Cobalt ferrites Electron hopping Kinetic dissolution Rietveld method X-ray anomalous scattering Dissolution Iron compounds Molecular structure Reaction kinetics Substitution reactions Synthesis (chemical) X ray scattering Cobalt ferrites Electron hopping Kinetic dissolution Rietveld method X-ray anomalous scattering Cobalt compounds |
| spellingShingle |
Cobalt ferrites Electron hopping Kinetic dissolution Rietveld method X-ray anomalous scattering Dissolution Iron compounds Molecular structure Reaction kinetics Substitution reactions Synthesis (chemical) X ray scattering Cobalt ferrites Electron hopping Kinetic dissolution Rietveld method X-ray anomalous scattering Cobalt compounds Sileo, E.E. García Rodenas, L. Paiva-Santos, C.O. Stephens, P.W. Morando, P.J. Blesa, M.A. Correlation of reactivity with structural factors in a series of Fe(II) substituted cobalt ferrites |
| topic_facet |
Cobalt ferrites Electron hopping Kinetic dissolution Rietveld method X-ray anomalous scattering Dissolution Iron compounds Molecular structure Reaction kinetics Substitution reactions Synthesis (chemical) X ray scattering Cobalt ferrites Electron hopping Kinetic dissolution Rietveld method X-ray anomalous scattering Cobalt compounds |
| description |
A series of powdered cobalt ferrites, CoxFe3-xO4 with 0.66≤x<1.00 containing different amounts of FeII, were synthesized by a mild procedure, and their Fe and Co site occupancies and structural characteristics were explored using X-ray anomalous scattering and the Rietveld refinement method. The dissolution kinetics, measured in 0.1 M oxalic acid aqueous solution at 70 °C, indicate in all cases the operation of a contracting volume rate law. The specific rates increased with the FeII content following approximately a second-order polynomial expression. This result suggests that the transfer of FeIII controls the dissolution rate, and that the leaching of a first layer of ions CoII and FeII leaves exposed a surface enriched in slower dissolving octahedral FeIII ions. Within this model, inner vicinal lattice FeII accelerates the rate of FeIII transfer via internal electron hopping. A chain mechanism, involving successive electron transfers, fits the data very well. © 2006 Elsevier Inc. All rights reserved. |
| format |
JOUR |
| author |
Sileo, E.E. García Rodenas, L. Paiva-Santos, C.O. Stephens, P.W. Morando, P.J. Blesa, M.A. |
| author_facet |
Sileo, E.E. García Rodenas, L. Paiva-Santos, C.O. Stephens, P.W. Morando, P.J. Blesa, M.A. |
| author_sort |
Sileo, E.E. |
| title |
Correlation of reactivity with structural factors in a series of Fe(II) substituted cobalt ferrites |
| title_short |
Correlation of reactivity with structural factors in a series of Fe(II) substituted cobalt ferrites |
| title_full |
Correlation of reactivity with structural factors in a series of Fe(II) substituted cobalt ferrites |
| title_fullStr |
Correlation of reactivity with structural factors in a series of Fe(II) substituted cobalt ferrites |
| title_full_unstemmed |
Correlation of reactivity with structural factors in a series of Fe(II) substituted cobalt ferrites |
| title_sort |
correlation of reactivity with structural factors in a series of fe(ii) substituted cobalt ferrites |
| url |
http://hdl.handle.net/20.500.12110/paper_00224596_v179_n7_p2237_Sileo |
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1782030542919696384 |