Surface electrochemical transformations on spinel iron oxide electrodes in aqueous solutions

The effect of potential and electrolyte composition on the surface stoichiometry in magnetite oxide electrodes has been investigated by a variety of electrochemical techniques: open-circuit potential, chronoamperometry, surface redox titration by galvanostatic pulses, electrochemical impedance spect...

Descripción completa

Guardado en:

Detalles Bibliográficos
Autores principales:	Castro, P.A., Vago, E.R., Calvo, E.J.
Formato:	JOUR
Acceso en línea:	http://hdl.handle.net/20.500.12110/paper_09565000_v92_n18_p3371_Castro
Aporte de:	Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) de Universidad de Buenos Aires

id	todo:paper_09565000_v92_n18_p3371_Castro
record_format	dspace
spelling	todo:paper_09565000_v92_n18_p3371_Castro2023-10-03T15:51:59Z Surface electrochemical transformations on spinel iron oxide electrodes in aqueous solutions Castro, P.A. Vago, E.R. Calvo, E.J. The effect of potential and electrolyte composition on the surface stoichiometry in magnetite oxide electrodes has been investigated by a variety of electrochemical techniques: open-circuit potential, chronoamperometry, surface redox titration by galvanostatic pulses, electrochemical impedance spectroscopy and electroreflectance. These studies revealed a continuous change in surface iron composition with potential that results in a low-frequency, potential-dependent pseudo-capacitance. The capacitance-potential curves for different electrolyte pH were analysed in terms of: (a) the iron spinel system Fe3-δO4 (0 ≤ δ ≤ 0.33) and (b) a modified Fe3O4 electrode with octahedral surface iron complexes, to accommodate the change of surface stoichiometry. The second model is consistent with the experimental data and the resulting dependence of FeII surface sites on potential and pH predicts the kinetics of O2 electroreduction on Fe3O4. Similar electrochemical behaviour of oxidized magnetite electrodes and passive iron in alkaline solutions has been found, which parallels the analogous kinetics observed for oxygen electroreduction on these oxides. Fil:Castro, P.A. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. Fil:Vago, E.R. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. Fil:Calvo, E.J. 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_09565000_v92_n18_p3371_Castro
institution	Universidad de Buenos Aires
institution_str	I-28
repository_str	R-134
collection	Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA)
description	The effect of potential and electrolyte composition on the surface stoichiometry in magnetite oxide electrodes has been investigated by a variety of electrochemical techniques: open-circuit potential, chronoamperometry, surface redox titration by galvanostatic pulses, electrochemical impedance spectroscopy and electroreflectance. These studies revealed a continuous change in surface iron composition with potential that results in a low-frequency, potential-dependent pseudo-capacitance. The capacitance-potential curves for different electrolyte pH were analysed in terms of: (a) the iron spinel system Fe3-δO4 (0 ≤ δ ≤ 0.33) and (b) a modified Fe3O4 electrode with octahedral surface iron complexes, to accommodate the change of surface stoichiometry. The second model is consistent with the experimental data and the resulting dependence of FeII surface sites on potential and pH predicts the kinetics of O2 electroreduction on Fe3O4. Similar electrochemical behaviour of oxidized magnetite electrodes and passive iron in alkaline solutions has been found, which parallels the analogous kinetics observed for oxygen electroreduction on these oxides.
format	JOUR
author	Castro, P.A. Vago, E.R. Calvo, E.J.
spellingShingle	Castro, P.A. Vago, E.R. Calvo, E.J. Surface electrochemical transformations on spinel iron oxide electrodes in aqueous solutions
author_facet	Castro, P.A. Vago, E.R. Calvo, E.J.
author_sort	Castro, P.A.
title	Surface electrochemical transformations on spinel iron oxide electrodes in aqueous solutions
title_short	Surface electrochemical transformations on spinel iron oxide electrodes in aqueous solutions
title_full	Surface electrochemical transformations on spinel iron oxide electrodes in aqueous solutions
title_fullStr	Surface electrochemical transformations on spinel iron oxide electrodes in aqueous solutions
title_full_unstemmed	Surface electrochemical transformations on spinel iron oxide electrodes in aqueous solutions
title_sort	surface electrochemical transformations on spinel iron oxide electrodes in aqueous solutions
url	http://hdl.handle.net/20.500.12110/paper_09565000_v92_n18_p3371_Castro
work_keys_str_mv	AT castropa surfaceelectrochemicaltransformationsonspinelironoxideelectrodesinaqueoussolutions AT vagoer surfaceelectrochemicaltransformationsonspinelironoxideelectrodesinaqueoussolutions AT calvoej surfaceelectrochemicaltransformationsonspinelironoxideelectrodesinaqueoussolutions
_version_	1782026077760126976

Surface electrochemical transformations on spinel iron oxide electrodes in aqueous solutions

Ejemplares similares