Combined voltammetry and in situ infrared spectroscopy of tetramethylthiourea on gold in aqueous acid solutions

Autores
Bolzán, Agustín Eduardo; Iwasita, T.; Arvia, Alejandro Jorge
Año de publicación
2005
Idioma
inglés
Tipo de recurso
artículo
Estado
versión publicada
Descripción
The voltammetric behaviour of tetramethylthiourea (TMTU) dissolved in aqueous perchloric and sulphuric acid solutions on polycrystalline gold combined with in situ Fourier transform infrared reflection absorption spectroscopy (FTIRRAS) was investigated. Conventional and triangular modulated voltammetry and rotating disc electrode data demonstrate the occurrence of two redox surface processes in the potential ranges −0.1 ≤ E ≤ −0.3 V and 0.7 ≤ E ≤ 0.8 V (versus SHE), respectively. These processes would involve the participation of TMTU adsorbates. The redox surface process observed in the range −0.1 to −0.3 V can be related to the electrosorption of TMTU. The absence of infrared absorption bands from these adsorbates agrees with a flat, almost parallel adsorption of TMTU molecules on gold that has been already reported. In the range 0.4 V ≤ E ≤ 0.8 V both electrochemical and spectroscopic data indicate the anodic formation of soluble gold–TMTU complex and tetramethylformamidine disulphide (TMFDS2+) ions presumably via Au(TMTU)+ adsorbates. The kinetics of soluble gold– TMTU complex ion formation is under diffusion control, whereas the formation of TMFDS2+ ions behaves as a rather irreversible process with the anodic slope, derived from current–potential curves, ∂E/∂ log I = 0.120 V decade−1 at 298 K. At E > 1.2 V, the global electro-oxidation of both TMTU and TMFDS2+ species yields carbon dioxide, sulphate ions and carbonyl-containing compounds, as indicated by IR spectra. These reactions involve the participation of oxygen-containing adsorbates produced from water electro-oxidation on gold.
Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas
Materia
Ciencias Exactas
Química
Tetramethylthiourea
Electro-oxidation
FTIRRAS
Gold
Electrodissolution
Nivel de accesibilidad
acceso abierto
Condiciones de uso
http://creativecommons.org/licenses/by-nc-sa/4.0/
Repositorio
SEDICI (UNLP)
Institución
Universidad Nacional de La Plata
OAI Identificador
oai:sedici.unlp.edu.ar:10915/119201

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oai_identifier_str oai:sedici.unlp.edu.ar:10915/119201
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repository_id_str 1329
network_name_str SEDICI (UNLP)
spelling Combined voltammetry and in situ infrared spectroscopy of tetramethylthiourea on gold in aqueous acid solutionsBolzán, Agustín EduardoIwasita, T.Arvia, Alejandro JorgeCiencias ExactasQuímicaTetramethylthioureaElectro-oxidationFTIRRASGoldElectrodissolutionThe voltammetric behaviour of tetramethylthiourea (TMTU) dissolved in aqueous perchloric and sulphuric acid solutions on polycrystalline gold combined with in situ Fourier transform infrared reflection absorption spectroscopy (FTIRRAS) was investigated. Conventional and triangular modulated voltammetry and rotating disc electrode data demonstrate the occurrence of two redox surface processes in the potential ranges −0.1 ≤ E ≤ −0.3 V and 0.7 ≤ E ≤ 0.8 V (versus SHE), respectively. These processes would involve the participation of TMTU adsorbates. The redox surface process observed in the range −0.1 to −0.3 V can be related to the electrosorption of TMTU. The absence of infrared absorption bands from these adsorbates agrees with a flat, almost parallel adsorption of TMTU molecules on gold that has been already reported. In the range 0.4 V ≤ E ≤ 0.8 V both electrochemical and spectroscopic data indicate the anodic formation of soluble gold–TMTU complex and tetramethylformamidine disulphide (TMFDS<sup>2+</sup>) ions presumably via Au(TMTU)<sup>+</sup> adsorbates. The kinetics of soluble gold– TMTU complex ion formation is under diffusion control, whereas the formation of TMFDS2+ ions behaves as a rather irreversible process with the anodic slope, derived from current–potential curves, ∂E/∂ log I = 0.120 V decade−1 at 298 K. At E > 1.2 V, the global electro-oxidation of both TMTU and TMFDS<sup>2+</sup> species yields carbon dioxide, sulphate ions and carbonyl-containing compounds, as indicated by IR spectra. These reactions involve the participation of oxygen-containing adsorbates produced from water electro-oxidation on gold.Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas2005info:eu-repo/semantics/articleinfo:eu-repo/semantics/publishedVersionArticulohttp://purl.org/coar/resource_type/c_6501info:ar-repo/semantics/articuloapplication/pdf1044-1058http://sedici.unlp.edu.ar/handle/10915/119201enginfo:eu-repo/semantics/altIdentifier/url/https://www.sciencedirect.com/science/article/abs/pii/S001346860500592Xinfo:eu-repo/semantics/altIdentifier/issn/0013-4686info:eu-repo/semantics/altIdentifier/doi/10.1016/j.electacta.2005.05.043info:eu-repo/semantics/openAccesshttp://creativecommons.org/licenses/by-nc-sa/4.0/Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International (CC BY-NC-SA 4.0)reponame:SEDICI (UNLP)instname:Universidad Nacional de La Platainstacron:UNLP2025-09-29T11:28:05Zoai:sedici.unlp.edu.ar:10915/119201Institucionalhttp://sedici.unlp.edu.ar/Universidad públicaNo correspondehttp://sedici.unlp.edu.ar/oai/snrdalira@sedici.unlp.edu.arArgentinaNo correspondeNo correspondeNo correspondeopendoar:13292025-09-29 11:28:05.875SEDICI (UNLP) - Universidad Nacional de La Platafalse
dc.title.none.fl_str_mv Combined voltammetry and in situ infrared spectroscopy of tetramethylthiourea on gold in aqueous acid solutions
title Combined voltammetry and in situ infrared spectroscopy of tetramethylthiourea on gold in aqueous acid solutions
spellingShingle Combined voltammetry and in situ infrared spectroscopy of tetramethylthiourea on gold in aqueous acid solutions
Bolzán, Agustín Eduardo
Ciencias Exactas
Química
Tetramethylthiourea
Electro-oxidation
FTIRRAS
Gold
Electrodissolution
title_short Combined voltammetry and in situ infrared spectroscopy of tetramethylthiourea on gold in aqueous acid solutions
title_full Combined voltammetry and in situ infrared spectroscopy of tetramethylthiourea on gold in aqueous acid solutions
title_fullStr Combined voltammetry and in situ infrared spectroscopy of tetramethylthiourea on gold in aqueous acid solutions
title_full_unstemmed Combined voltammetry and in situ infrared spectroscopy of tetramethylthiourea on gold in aqueous acid solutions
title_sort Combined voltammetry and in situ infrared spectroscopy of tetramethylthiourea on gold in aqueous acid solutions
dc.creator.none.fl_str_mv Bolzán, Agustín Eduardo
Iwasita, T.
Arvia, Alejandro Jorge
author Bolzán, Agustín Eduardo
author_facet Bolzán, Agustín Eduardo
Iwasita, T.
Arvia, Alejandro Jorge
author_role author
author2 Iwasita, T.
Arvia, Alejandro Jorge
author2_role author
author
dc.subject.none.fl_str_mv Ciencias Exactas
Química
Tetramethylthiourea
Electro-oxidation
FTIRRAS
Gold
Electrodissolution
topic Ciencias Exactas
Química
Tetramethylthiourea
Electro-oxidation
FTIRRAS
Gold
Electrodissolution
dc.description.none.fl_txt_mv The voltammetric behaviour of tetramethylthiourea (TMTU) dissolved in aqueous perchloric and sulphuric acid solutions on polycrystalline gold combined with in situ Fourier transform infrared reflection absorption spectroscopy (FTIRRAS) was investigated. Conventional and triangular modulated voltammetry and rotating disc electrode data demonstrate the occurrence of two redox surface processes in the potential ranges −0.1 ≤ E ≤ −0.3 V and 0.7 ≤ E ≤ 0.8 V (versus SHE), respectively. These processes would involve the participation of TMTU adsorbates. The redox surface process observed in the range −0.1 to −0.3 V can be related to the electrosorption of TMTU. The absence of infrared absorption bands from these adsorbates agrees with a flat, almost parallel adsorption of TMTU molecules on gold that has been already reported. In the range 0.4 V ≤ E ≤ 0.8 V both electrochemical and spectroscopic data indicate the anodic formation of soluble gold–TMTU complex and tetramethylformamidine disulphide (TMFDS<sup>2+</sup>) ions presumably via Au(TMTU)<sup>+</sup> adsorbates. The kinetics of soluble gold– TMTU complex ion formation is under diffusion control, whereas the formation of TMFDS2+ ions behaves as a rather irreversible process with the anodic slope, derived from current–potential curves, ∂E/∂ log I = 0.120 V decade−1 at 298 K. At E > 1.2 V, the global electro-oxidation of both TMTU and TMFDS<sup>2+</sup> species yields carbon dioxide, sulphate ions and carbonyl-containing compounds, as indicated by IR spectra. These reactions involve the participation of oxygen-containing adsorbates produced from water electro-oxidation on gold.
Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas
description The voltammetric behaviour of tetramethylthiourea (TMTU) dissolved in aqueous perchloric and sulphuric acid solutions on polycrystalline gold combined with in situ Fourier transform infrared reflection absorption spectroscopy (FTIRRAS) was investigated. Conventional and triangular modulated voltammetry and rotating disc electrode data demonstrate the occurrence of two redox surface processes in the potential ranges −0.1 ≤ E ≤ −0.3 V and 0.7 ≤ E ≤ 0.8 V (versus SHE), respectively. These processes would involve the participation of TMTU adsorbates. The redox surface process observed in the range −0.1 to −0.3 V can be related to the electrosorption of TMTU. The absence of infrared absorption bands from these adsorbates agrees with a flat, almost parallel adsorption of TMTU molecules on gold that has been already reported. In the range 0.4 V ≤ E ≤ 0.8 V both electrochemical and spectroscopic data indicate the anodic formation of soluble gold–TMTU complex and tetramethylformamidine disulphide (TMFDS<sup>2+</sup>) ions presumably via Au(TMTU)<sup>+</sup> adsorbates. The kinetics of soluble gold– TMTU complex ion formation is under diffusion control, whereas the formation of TMFDS2+ ions behaves as a rather irreversible process with the anodic slope, derived from current–potential curves, ∂E/∂ log I = 0.120 V decade−1 at 298 K. At E > 1.2 V, the global electro-oxidation of both TMTU and TMFDS<sup>2+</sup> species yields carbon dioxide, sulphate ions and carbonyl-containing compounds, as indicated by IR spectra. These reactions involve the participation of oxygen-containing adsorbates produced from water electro-oxidation on gold.
publishDate 2005
dc.date.none.fl_str_mv 2005
dc.type.none.fl_str_mv info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
Articulo
http://purl.org/coar/resource_type/c_6501
info:ar-repo/semantics/articulo
format article
status_str publishedVersion
dc.identifier.none.fl_str_mv http://sedici.unlp.edu.ar/handle/10915/119201
url http://sedici.unlp.edu.ar/handle/10915/119201
dc.language.none.fl_str_mv eng
language eng
dc.relation.none.fl_str_mv info:eu-repo/semantics/altIdentifier/url/https://www.sciencedirect.com/science/article/abs/pii/S001346860500592X
info:eu-repo/semantics/altIdentifier/issn/0013-4686
info:eu-repo/semantics/altIdentifier/doi/10.1016/j.electacta.2005.05.043
dc.rights.none.fl_str_mv info:eu-repo/semantics/openAccess
http://creativecommons.org/licenses/by-nc-sa/4.0/
Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International (CC BY-NC-SA 4.0)
eu_rights_str_mv openAccess
rights_invalid_str_mv http://creativecommons.org/licenses/by-nc-sa/4.0/
Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International (CC BY-NC-SA 4.0)
dc.format.none.fl_str_mv application/pdf
1044-1058
dc.source.none.fl_str_mv reponame:SEDICI (UNLP)
instname:Universidad Nacional de La Plata
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repository.name.fl_str_mv SEDICI (UNLP) - Universidad Nacional de La Plata
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