Electrodic reduction of core-shell ferrite magnetic nanoparticlesDr F. A. Tourinho deceased during the redaction of this paper but, as an electrochemistry specialist, he was at the origin of this work. We dedicate this article to his memory

We present square-wave voltammetry (SWV) and controlled potential coulometry (bulk electrolysis) experiments performed on maghemite and ferrite nanoparticles of core-shell-type MFe 2 O 4 @γ-Fe 2 O 3 (where M = Mn 2+ , Co 2+ , Cu 2+ or Zn 2+ ), dispersed in aqueous media. The potential position of th...

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Main Authors: Filomeno, Cleber Lopes, Marinho, Epitácio Pinto, Aquino, Renata, Silva, Franciscarlos Gomes da, Dubois, Emmanuelle, Depeyrot, Jerome, Campos, Alex Fabiano Cortez
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Summary:We present square-wave voltammetry (SWV) and controlled potential coulometry (bulk electrolysis) experiments performed on maghemite and ferrite nanoparticles of core-shell-type MFe 2 O 4 @γ-Fe 2 O 3 (where M = Mn 2+ , Co 2+ , Cu 2+ or Zn 2+ ), dispersed in aqueous media. The potential position of the iron( iii ) reduction peak identified in SWV measurements does not depend on the core chemical composition. No variations with size and polydispersity are detected. The shift of the reduction peak observed in coordinated configurations is related to the iron oxidizing strength. The electrolysis performed at a controlled potential of NPs indicates that only a fraction of iron( iii ) is reduced. Using the individual net charge deduced from the controlled potential coulometry measurements, we determine the thickness of the surface shell, which is electrolyzed. The electro-activity of MFe 2 O 4 @γ-Fe 2 O 3 (M = Mn, Co, Cu and Zn) nanoparticles occurs at the surface layer and reflects the surface environment.
ISSN:1144-0546
1369-9261
DOI:10.1039/c5nj03659c