Electrochemical processes at gold ∣ thiourea-containing aqueous acid solution interfaces

Autores
Bolzán, Agustín Eduardo; Piatti, Roberto C. V.; Arvia, Alejandro Jorge
Año de publicación
2003
Idioma
inglés
Tipo de recurso
artículo
Estado
versión publicada
Descripción
The electrochemical behaviour of thiourea (TU) on gold in acid solutions is investigated in the range −0.2 to 1.7 V (versus standard hydrogen electrode) by conventional and triangularly potential modulated voltammetry, rest potential (Erest) measurements, rotating disk and rotating ring-disk techniques. The value of Erest is determined by an electrochemical reaction involving formamidine disulphide (FDS), adsorbed TU and soluble [Au(TU)2]+ species. For TU concentrations (cTU) in the range 1⩽cTU⩽50 mM, Erest decreases linearly with log cTU with a slope of approximately −0.090 V decade−1, while in the range 0.1⩽cTU⩽0.25 mM, it approaches −0.120 V decade−1. Conventional and triangularly modulated voltammetry data indicate the quasi-reversible adsorption of TU occurring in the range −0.2⩽E⩽0.1 V, and the electro-oxidation of TU to FDS in the range 0.2⩽E⩽0.9 V, occurring simultaneously with the electrodissolution of gold yielding soluble [Au(TU)2]+ species. Both the electro-oxidation of TU and the electrodissolution of gold are under mass transfer control influenced by adsorbate formation. Different adsorbates from TU are produced depending on the adsorption potential and time. The electro-oxidation of these adsorbates in the range 0.9–1.7 V yields sulphate, carbon dioxide and CN residues. Reaction products are consistent with previous STM and FTIRS data. Comparative electrochemical data from FDS- and sulphide-containing solutions are also presented. Reaction pathways in which the participation of different adsorbates is considered, are discussed.
Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas
Materia
Ciencias Exactas
Química
Gold
Thiourea
Adsorbates
Formamidine disulphide
Electro-oxidation
Dissolution
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:10915/119504

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repository_id_str 1329
network_name_str SEDICI (UNLP)
spelling Electrochemical processes at gold ∣ thiourea-containing aqueous acid solution interfacesBolzán, Agustín EduardoPiatti, Roberto C. V.Arvia, Alejandro JorgeCiencias ExactasQuímicaGoldThioureaAdsorbatesFormamidine disulphideElectro-oxidationDissolutionThe electrochemical behaviour of thiourea (TU) on gold in acid solutions is investigated in the range −0.2 to 1.7 V (versus standard hydrogen electrode) by conventional and triangularly potential modulated voltammetry, rest potential (Erest) measurements, rotating disk and rotating ring-disk techniques. The value of E<sub>rest</sub> is determined by an electrochemical reaction involving formamidine disulphide (FDS), adsorbed TU and soluble [Au(TU)<sub>2</sub>]<sup>+</sup> species. For TU concentrations (<sup>c</sup>TU) in the range 1⩽<sup>c</sup>TU⩽50 mM, Erest decreases linearly with log <sup>c</sup>TU with a slope of approximately −0.090 V decade<sup>−1</sup>, while in the range 0.1⩽<sup>c</sup>TU⩽0.25 mM, it approaches −0.120 V decade<sup>−1</sup>. Conventional and triangularly modulated voltammetry data indicate the quasi-reversible adsorption of TU occurring in the range −0.2⩽E⩽0.1 V, and the electro-oxidation of TU to FDS in the range 0.2⩽E⩽0.9 V, occurring simultaneously with the electrodissolution of gold yielding soluble [Au(TU)<sub>2</sub>]<sup>+</sup> species. Both the electro-oxidation of TU and the electrodissolution of gold are under mass transfer control influenced by adsorbate formation. Different adsorbates from TU are produced depending on the adsorption potential and time. The electro-oxidation of these adsorbates in the range 0.9–1.7 V yields sulphate, carbon dioxide and CN residues. Reaction products are consistent with previous STM and FTIRS data. Comparative electrochemical data from FDS- and sulphide-containing solutions are also presented. Reaction pathways in which the participation of different adsorbates is considered, are discussed.Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas2003info:eu-repo/semantics/articleinfo:eu-repo/semantics/publishedVersionArticulohttp://purl.org/coar/resource_type/c_6501info:ar-repo/semantics/articuloapplication/pdf19-34http://sedici.unlp.edu.ar/handle/10915/119504enginfo:eu-repo/semantics/altIdentifier/issn/1572-6657info:eu-repo/semantics/altIdentifier/doi/10.1016/S0022-0728(03)00020-2info: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:UNLP2025-09-29T11:28:14Zoai:sedici.unlp.edu.ar:10915/119504Institucionalhttp://sedici.unlp.edu.ar/Universidad públicaNo correspondehttp://sedici.unlp.edu.ar/oai/snrdalira@sedici.unlp.edu.arArgentinaNo correspondeNo correspondeNo correspondeopendoar:13292025-09-29 11:28:14.621SEDICI (UNLP) - Universidad Nacional de La Platafalse
dc.title.none.fl_str_mv Electrochemical processes at gold ∣ thiourea-containing aqueous acid solution interfaces
title Electrochemical processes at gold ∣ thiourea-containing aqueous acid solution interfaces
spellingShingle Electrochemical processes at gold ∣ thiourea-containing aqueous acid solution interfaces
Bolzán, Agustín Eduardo
Ciencias Exactas
Química
Gold
Thiourea
Adsorbates
Formamidine disulphide
Electro-oxidation
Dissolution
title_short Electrochemical processes at gold ∣ thiourea-containing aqueous acid solution interfaces
title_full Electrochemical processes at gold ∣ thiourea-containing aqueous acid solution interfaces
title_fullStr Electrochemical processes at gold ∣ thiourea-containing aqueous acid solution interfaces
title_full_unstemmed Electrochemical processes at gold ∣ thiourea-containing aqueous acid solution interfaces
title_sort Electrochemical processes at gold ∣ thiourea-containing aqueous acid solution interfaces
dc.creator.none.fl_str_mv Bolzán, Agustín Eduardo
Piatti, Roberto C. V.
Arvia, Alejandro Jorge
author Bolzán, Agustín Eduardo
author_facet Bolzán, Agustín Eduardo
Piatti, Roberto C. V.
Arvia, Alejandro Jorge
author_role author
author2 Piatti, Roberto C. V.
Arvia, Alejandro Jorge
author2_role author
author
dc.subject.none.fl_str_mv Ciencias Exactas
Química
Gold
Thiourea
Adsorbates
Formamidine disulphide
Electro-oxidation
Dissolution
topic Ciencias Exactas
Química
Gold
Thiourea
Adsorbates
Formamidine disulphide
Electro-oxidation
Dissolution
dc.description.none.fl_txt_mv The electrochemical behaviour of thiourea (TU) on gold in acid solutions is investigated in the range −0.2 to 1.7 V (versus standard hydrogen electrode) by conventional and triangularly potential modulated voltammetry, rest potential (Erest) measurements, rotating disk and rotating ring-disk techniques. The value of E<sub>rest</sub> is determined by an electrochemical reaction involving formamidine disulphide (FDS), adsorbed TU and soluble [Au(TU)<sub>2</sub>]<sup>+</sup> species. For TU concentrations (<sup>c</sup>TU) in the range 1⩽<sup>c</sup>TU⩽50 mM, Erest decreases linearly with log <sup>c</sup>TU with a slope of approximately −0.090 V decade<sup>−1</sup>, while in the range 0.1⩽<sup>c</sup>TU⩽0.25 mM, it approaches −0.120 V decade<sup>−1</sup>. Conventional and triangularly modulated voltammetry data indicate the quasi-reversible adsorption of TU occurring in the range −0.2⩽E⩽0.1 V, and the electro-oxidation of TU to FDS in the range 0.2⩽E⩽0.9 V, occurring simultaneously with the electrodissolution of gold yielding soluble [Au(TU)<sub>2</sub>]<sup>+</sup> species. Both the electro-oxidation of TU and the electrodissolution of gold are under mass transfer control influenced by adsorbate formation. Different adsorbates from TU are produced depending on the adsorption potential and time. The electro-oxidation of these adsorbates in the range 0.9–1.7 V yields sulphate, carbon dioxide and CN residues. Reaction products are consistent with previous STM and FTIRS data. Comparative electrochemical data from FDS- and sulphide-containing solutions are also presented. Reaction pathways in which the participation of different adsorbates is considered, are discussed.
Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas
description The electrochemical behaviour of thiourea (TU) on gold in acid solutions is investigated in the range −0.2 to 1.7 V (versus standard hydrogen electrode) by conventional and triangularly potential modulated voltammetry, rest potential (Erest) measurements, rotating disk and rotating ring-disk techniques. The value of E<sub>rest</sub> is determined by an electrochemical reaction involving formamidine disulphide (FDS), adsorbed TU and soluble [Au(TU)<sub>2</sub>]<sup>+</sup> species. For TU concentrations (<sup>c</sup>TU) in the range 1⩽<sup>c</sup>TU⩽50 mM, Erest decreases linearly with log <sup>c</sup>TU with a slope of approximately −0.090 V decade<sup>−1</sup>, while in the range 0.1⩽<sup>c</sup>TU⩽0.25 mM, it approaches −0.120 V decade<sup>−1</sup>. Conventional and triangularly modulated voltammetry data indicate the quasi-reversible adsorption of TU occurring in the range −0.2⩽E⩽0.1 V, and the electro-oxidation of TU to FDS in the range 0.2⩽E⩽0.9 V, occurring simultaneously with the electrodissolution of gold yielding soluble [Au(TU)<sub>2</sub>]<sup>+</sup> species. Both the electro-oxidation of TU and the electrodissolution of gold are under mass transfer control influenced by adsorbate formation. Different adsorbates from TU are produced depending on the adsorption potential and time. The electro-oxidation of these adsorbates in the range 0.9–1.7 V yields sulphate, carbon dioxide and CN residues. Reaction products are consistent with previous STM and FTIRS data. Comparative electrochemical data from FDS- and sulphide-containing solutions are also presented. Reaction pathways in which the participation of different adsorbates is considered, are discussed.
publishDate 2003
dc.date.none.fl_str_mv 2003
dc.type.none.fl_str_mv info:eu-repo/semantics/article
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info:eu-repo/semantics/altIdentifier/doi/10.1016/S0022-0728(03)00020-2
dc.rights.none.fl_str_mv info:eu-repo/semantics/openAccess
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Creative Commons Attribution 4.0 International (CC BY 4.0)
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