Adsorption and electro-oxidation of N-alkyl and N,N’-dialkyl thioureas on gold electrodes in acid solutions. A combined FTIRRAS and voltammetry study

The adsorption and electro-oxidation of N-alkyl and N,N’-dialkyl thioureas on polycrystalline gold in aqueous acid solutions is studied by Fourier-transformed infrared reflection absorption spectroscopy (FTIRRAS) and voltammetry. The potential ranges for different electrochemical processes, includin...

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Detalles Bibliográficos
Autores principales: Bolzán, Agustín Eduardo, Arvia, Alejandro Jorge
Formato: Articulo
Lenguaje:Inglés
Publicado: 2008
Materias:
Ciencias Exactas
Química
Methylthiourea
Dimethylthiourea
Ethylthiourea
Diethylthiourea
Electro-oxidation
Adsorbates
Gold electrode
FTIRRAS
Acceso en línea:http://sedici.unlp.edu.ar/handle/10915/119002
Aporte de:
SEDICI (UNLP) de Universidad Nacional de La Plata
id I19-R120-10915-119002
record_format dspace
institution Universidad Nacional de La Plata
institution_str I-19
repository_str R-120
collection SEDICI (UNLP)
language Inglés
topic Ciencias Exactas
Química
Methylthiourea
Dimethylthiourea
Ethylthiourea
Diethylthiourea
Electro-oxidation
Adsorbates
Gold electrode
FTIRRAS
spellingShingle Ciencias Exactas
Química
Methylthiourea
Dimethylthiourea
Ethylthiourea
Diethylthiourea
Electro-oxidation
Adsorbates
Gold electrode
FTIRRAS
Bolzán, Agustín Eduardo
Arvia, Alejandro Jorge
Adsorption and electro-oxidation of N-alkyl and N,N’-dialkyl thioureas on gold electrodes in acid solutions. A combined FTIRRAS and voltammetry study
topic_facet Ciencias Exactas
Química
Methylthiourea
Dimethylthiourea
Ethylthiourea
Diethylthiourea
Electro-oxidation
Adsorbates
Gold electrode
FTIRRAS
description The adsorption and electro-oxidation of N-alkyl and N,N’-dialkyl thioureas on polycrystalline gold in aqueous acid solutions is studied by Fourier-transformed infrared reflection absorption spectroscopy (FTIRRAS) and voltammetry. The potential ranges for different electrochemical processes, including electrodissolution of gold and electro-oxidation of thioureas, are determined by cyclic voltammetry. The gradual depletion of thioureas and the progressive formation of products from adsorbed and soluble species in the thin solution layer in contact with the electrode are followed through changes in band intensity of infrared (IR) spectra. Adsorbates of thioureas are formed at 0.05 Vand remain on the surface up to E=1.2 V, a potential at which their electro-oxidation takes place. Irrespective of the type of thiourea, the first electro-oxidation process from soluble thioureas starts at ca. 0.45 V with the formation of their respective disulphide. This process is preceded by the electrodissolution of gold via the formation of gold–thiourea soluble complex species. From ca. 1.2 V upwards the second electro-oxidation process results in the formation of carbon dioxide, sulphate ions and C≡N-containing species. The latter are produced only from N-alkyl thioureas, in which the presence of free amine groups makes the formation of a C≡N bond possible, as a previous stage to the production of carbon dioxide and sulphate ions as final products. From the correlation between voltammetric and spectroscopic data a general reaction pathway for the adsorption of thioureas and their electro-oxidation on gold is advanced.
format Articulo
Articulo
author Bolzán, Agustín Eduardo
Arvia, Alejandro Jorge
author_facet Bolzán, Agustín Eduardo
Arvia, Alejandro Jorge
author_sort Bolzán, Agustín Eduardo
title Adsorption and electro-oxidation of N-alkyl and N,N’-dialkyl thioureas on gold electrodes in acid solutions. A combined FTIRRAS and voltammetry study
title_short Adsorption and electro-oxidation of N-alkyl and N,N’-dialkyl thioureas on gold electrodes in acid solutions. A combined FTIRRAS and voltammetry study
title_full Adsorption and electro-oxidation of N-alkyl and N,N’-dialkyl thioureas on gold electrodes in acid solutions. A combined FTIRRAS and voltammetry study
title_fullStr Adsorption and electro-oxidation of N-alkyl and N,N’-dialkyl thioureas on gold electrodes in acid solutions. A combined FTIRRAS and voltammetry study
title_full_unstemmed Adsorption and electro-oxidation of N-alkyl and N,N’-dialkyl thioureas on gold electrodes in acid solutions. A combined FTIRRAS and voltammetry study
title_sort adsorption and electro-oxidation of n-alkyl and n,n’-dialkyl thioureas on gold electrodes in acid solutions. a combined ftirras and voltammetry study
publishDate 2008
url http://sedici.unlp.edu.ar/handle/10915/119002
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AT arviaalejandrojorge adsorptionandelectrooxidationofnalkylandnndialkylthioureasongoldelectrodesinacidsolutionsacombinedftirrasandvoltammetrystudy
bdutipo_str Repositorios
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