Electrochemical impedance spectroscopy of thiourea electro-oxidation on copper electrodes in aqueous 0.5 M sulphuric acid

Autores
Gassa, Liliana Mabel; Lambi, J. N.; Bolzán, Agustín Eduardo; Arvia, Alejandro Jorge
Año de publicación
2002
Idioma
inglés
Tipo de recurso
artículo
Estado
versión publicada
Descripción
The anodisation of copper electrodes in aqueous thiourea (TU) containing 0.5 M sulphuric acid is studied by electrochemical impedance spectroscopy (EIS) combined with rotating disk electrode and ring-disk electrode, SEM and EDAX techniques. For E<−0.35 V (vs. MSE), Nyquist plots show two time constants. The first one, which appears at high frequencies, involves the contribution of the double layer capacity and the charge transfer resistance related to the electro-oxidation of TU to formamidine disulphide (FDS). The second time constant, which is observed at low frequencies, is related to complex electrochemical and chemical processes following TU electro-oxidation to FDS. Depending on the applied potential, this time constant can be assigned to either an electroadsorption process from TU electro-oxidation products or an electrochemical process under diffusion through an anodic film. At high TU concentration, the low frequency time constant corresponds to the typical response of a pure capacitor due to the formation of a thick anodic film under a diffusion controlled process. In this case, for E≥−0.35 V, Nyquist plots exhibit at least three time constants and an inductive loop. The inductive loop is due to surface relaxation associated with copper pitting. The formation of different types of anodic films is confirmed by SEM observations. EIS results are consistent with the complex reaction pathway previously proposed for the anodisation of copper in aqueous TU-containing acid solutions.
Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas
Materia
Química
Ciencias Exactas
Thiourea
Copper
Electrochemical impedance spectroscopy
Electro-oxidation
Anodic films
Nivel de accesibilidad
acceso abierto
Condiciones de uso
http://creativecommons.org/licenses/by/4.0/
Repositorio
SEDICI (UNLP)
Institución
Universidad Nacional de La Plata
OAI Identificador
oai:sedici.unlp.edu.ar:10915/119469

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spelling Electrochemical impedance spectroscopy of thiourea electro-oxidation on copper electrodes in aqueous 0.5 M sulphuric acidGassa, Liliana MabelLambi, J. N.Bolzán, Agustín EduardoArvia, Alejandro JorgeQuímicaCiencias ExactasThioureaCopperElectrochemical impedance spectroscopyElectro-oxidationAnodic filmsThe anodisation of copper electrodes in aqueous thiourea (TU) containing 0.5 M sulphuric acid is studied by electrochemical impedance spectroscopy (EIS) combined with rotating disk electrode and ring-disk electrode, SEM and EDAX techniques. For E<−0.35 V (vs. MSE), Nyquist plots show two time constants. The first one, which appears at high frequencies, involves the contribution of the double layer capacity and the charge transfer resistance related to the electro-oxidation of TU to formamidine disulphide (FDS). The second time constant, which is observed at low frequencies, is related to complex electrochemical and chemical processes following TU electro-oxidation to FDS. Depending on the applied potential, this time constant can be assigned to either an electroadsorption process from TU electro-oxidation products or an electrochemical process under diffusion through an anodic film. At high TU concentration, the low frequency time constant corresponds to the typical response of a pure capacitor due to the formation of a thick anodic film under a diffusion controlled process. In this case, for E≥−0.35 V, Nyquist plots exhibit at least three time constants and an inductive loop. The inductive loop is due to surface relaxation associated with copper pitting. The formation of different types of anodic films is confirmed by SEM observations. EIS results are consistent with the complex reaction pathway previously proposed for the anodisation of copper in aqueous TU-containing acid solutions.Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas2002info:eu-repo/semantics/articleinfo:eu-repo/semantics/publishedVersionArticulohttp://purl.org/coar/resource_type/c_6501info:ar-repo/semantics/articuloapplication/pdf71-84http://sedici.unlp.edu.ar/handle/10915/119469enginfo:eu-repo/semantics/altIdentifier/issn/1572-6657info:eu-repo/semantics/altIdentifier/doi/10.1016/S0022-0728(02)00829-Xinfo:eu-repo/semantics/openAccesshttp://creativecommons.org/licenses/by/4.0/Creative Commons Attribution 4.0 International (CC BY 4.0)reponame:SEDICI (UNLP)instname:Universidad Nacional de La Platainstacron:UNLP2025-09-29T11:28:10Zoai:sedici.unlp.edu.ar:10915/119469Institucionalhttp://sedici.unlp.edu.ar/Universidad públicaNo correspondehttp://sedici.unlp.edu.ar/oai/snrdalira@sedici.unlp.edu.arArgentinaNo correspondeNo correspondeNo correspondeopendoar:13292025-09-29 11:28:10.864SEDICI (UNLP) - Universidad Nacional de La Platafalse
dc.title.none.fl_str_mv Electrochemical impedance spectroscopy of thiourea electro-oxidation on copper electrodes in aqueous 0.5 M sulphuric acid
title Electrochemical impedance spectroscopy of thiourea electro-oxidation on copper electrodes in aqueous 0.5 M sulphuric acid
spellingShingle Electrochemical impedance spectroscopy of thiourea electro-oxidation on copper electrodes in aqueous 0.5 M sulphuric acid
Gassa, Liliana Mabel
Química
Ciencias Exactas
Thiourea
Copper
Electrochemical impedance spectroscopy
Electro-oxidation
Anodic films
title_short Electrochemical impedance spectroscopy of thiourea electro-oxidation on copper electrodes in aqueous 0.5 M sulphuric acid
title_full Electrochemical impedance spectroscopy of thiourea electro-oxidation on copper electrodes in aqueous 0.5 M sulphuric acid
title_fullStr Electrochemical impedance spectroscopy of thiourea electro-oxidation on copper electrodes in aqueous 0.5 M sulphuric acid
title_full_unstemmed Electrochemical impedance spectroscopy of thiourea electro-oxidation on copper electrodes in aqueous 0.5 M sulphuric acid
title_sort Electrochemical impedance spectroscopy of thiourea electro-oxidation on copper electrodes in aqueous 0.5 M sulphuric acid
dc.creator.none.fl_str_mv Gassa, Liliana Mabel
Lambi, J. N.
Bolzán, Agustín Eduardo
Arvia, Alejandro Jorge
author Gassa, Liliana Mabel
author_facet Gassa, Liliana Mabel
Lambi, J. N.
Bolzán, Agustín Eduardo
Arvia, Alejandro Jorge
author_role author
author2 Lambi, J. N.
Bolzán, Agustín Eduardo
Arvia, Alejandro Jorge
author2_role author
author
author
dc.subject.none.fl_str_mv Química
Ciencias Exactas
Thiourea
Copper
Electrochemical impedance spectroscopy
Electro-oxidation
Anodic films
topic Química
Ciencias Exactas
Thiourea
Copper
Electrochemical impedance spectroscopy
Electro-oxidation
Anodic films
dc.description.none.fl_txt_mv The anodisation of copper electrodes in aqueous thiourea (TU) containing 0.5 M sulphuric acid is studied by electrochemical impedance spectroscopy (EIS) combined with rotating disk electrode and ring-disk electrode, SEM and EDAX techniques. For E<−0.35 V (vs. MSE), Nyquist plots show two time constants. The first one, which appears at high frequencies, involves the contribution of the double layer capacity and the charge transfer resistance related to the electro-oxidation of TU to formamidine disulphide (FDS). The second time constant, which is observed at low frequencies, is related to complex electrochemical and chemical processes following TU electro-oxidation to FDS. Depending on the applied potential, this time constant can be assigned to either an electroadsorption process from TU electro-oxidation products or an electrochemical process under diffusion through an anodic film. At high TU concentration, the low frequency time constant corresponds to the typical response of a pure capacitor due to the formation of a thick anodic film under a diffusion controlled process. In this case, for E≥−0.35 V, Nyquist plots exhibit at least three time constants and an inductive loop. The inductive loop is due to surface relaxation associated with copper pitting. The formation of different types of anodic films is confirmed by SEM observations. EIS results are consistent with the complex reaction pathway previously proposed for the anodisation of copper in aqueous TU-containing acid solutions.
Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas
description The anodisation of copper electrodes in aqueous thiourea (TU) containing 0.5 M sulphuric acid is studied by electrochemical impedance spectroscopy (EIS) combined with rotating disk electrode and ring-disk electrode, SEM and EDAX techniques. For E<−0.35 V (vs. MSE), Nyquist plots show two time constants. The first one, which appears at high frequencies, involves the contribution of the double layer capacity and the charge transfer resistance related to the electro-oxidation of TU to formamidine disulphide (FDS). The second time constant, which is observed at low frequencies, is related to complex electrochemical and chemical processes following TU electro-oxidation to FDS. Depending on the applied potential, this time constant can be assigned to either an electroadsorption process from TU electro-oxidation products or an electrochemical process under diffusion through an anodic film. At high TU concentration, the low frequency time constant corresponds to the typical response of a pure capacitor due to the formation of a thick anodic film under a diffusion controlled process. In this case, for E≥−0.35 V, Nyquist plots exhibit at least three time constants and an inductive loop. The inductive loop is due to surface relaxation associated with copper pitting. The formation of different types of anodic films is confirmed by SEM observations. EIS results are consistent with the complex reaction pathway previously proposed for the anodisation of copper in aqueous TU-containing acid solutions.
publishDate 2002
dc.date.none.fl_str_mv 2002
dc.type.none.fl_str_mv info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
Articulo
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info:ar-repo/semantics/articulo
format article
status_str publishedVersion
dc.identifier.none.fl_str_mv http://sedici.unlp.edu.ar/handle/10915/119469
url http://sedici.unlp.edu.ar/handle/10915/119469
dc.language.none.fl_str_mv eng
language eng
dc.relation.none.fl_str_mv info:eu-repo/semantics/altIdentifier/issn/1572-6657
info:eu-repo/semantics/altIdentifier/doi/10.1016/S0022-0728(02)00829-X
dc.rights.none.fl_str_mv info:eu-repo/semantics/openAccess
http://creativecommons.org/licenses/by/4.0/
Creative Commons Attribution 4.0 International (CC BY 4.0)
eu_rights_str_mv openAccess
rights_invalid_str_mv http://creativecommons.org/licenses/by/4.0/
Creative Commons Attribution 4.0 International (CC BY 4.0)
dc.format.none.fl_str_mv application/pdf
71-84
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repository.name.fl_str_mv SEDICI (UNLP) - Universidad Nacional de La Plata
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