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

Bolzán, Agustín Eduardo; Piatti, Roberto C. V.; Arvía, Alejandro Jorge

doi:10.1016/s0022-0728(03)00020-2

Cited by 38 publications

(28 citation statements)

References 49 publications

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“…These substances are classical additives for the electrodeposition of copper and other metals [8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23], corrosion inhibitors, vulcanization accelerators, components of fertilizers, pharmaceuticals, pesticides and herbicides [2,3,5,24].…”

Section: Introductionmentioning

confidence: 99%

“…Many studies have been carried out, predominantly in acidic media [8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23], which have been concerned with the voltammetric aspects of the correlation between the electrochemical behaviour of TU and various electrode systems. The dynamic electrochemistry of the systems consisting of thiourea-electrode in an alkaline medium has been specifically studied only for Pt, Au, Ag and boron-doped diamond BDD electrodes to highlight electrode behaviour, and even for amperometric detection [3,4,5,6,7].…”

Section: Introductionmentioning

confidence: 99%

“…Isolated studies regarding the behaviour of these electrodes in alkaline and neutral media [4][5][6] have suggested the intricate interfacial aspects and ligand bonding of thiourea, and some modifications of surface structure considered as adsorption effects [20,[27][28][29]. Copper electrodes and thiourea have been explored mainly from the point of view of cathodic processes and anodic behaviour in acidic media [8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23], but not in alkaline media.…”

Section: Introductionmentioning

confidence: 99%

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Amperometric determination of thiourea in alkaline media on a copper oxide–copper electrode

2006

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A copper oxide-copper electrode was tested in alkaline media for the anodic electrochemical detection of thiourea (TU). The correlation between the history of the electrode and potential range for optimum sensing of the particular susceptible species was analysed by electrochemical and surface layer techniques. The chemical composition and morphology of surface layers were examined using the SEM/EDX technique. Electrochemical data were obtained by cyclic voltammetry (CV) and chronoamperometry (CA). The linear calibration plots for an amperometric detection of TU in a delimited potential range, using CV and CA, were obtained for the 1-8 mM concentration range. Some considerations on the correlation between TU, electrode formation and polarization conditions are proposed. A copper oxide-copper electrode can be used as an inexpensive alternative for amperometric determination of TU in alkaline media without fouling the electrode surface.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Amperometric determination of thiourea in alkaline media on a copper oxide–copper electrode

2006

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“…Thiourea is widely known to be a complexing agent and to affect both electrode kinetics and deposit properties significantly [2][3][4][5]. It is also known to undergo slow decomposition in aqueous solutions as a result of which sulfur-containing impurities are formed [6,7].…”

Section: Introductionmentioning

confidence: 99%

Using an electrode with renewable surface for study of silver reduction from acid thiourea solutions

Zelinsky

Ershov

2007

J Appl Electrochem

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Sulfur-containing thiourea (TU) decomposition products exert a considerable effect on the silver electroreduction rate in TU solutions. The technique of removing a thin layer from a metal electrode in-situ at a fixed electrode potential makes it possible to minimize the influence of adsorbed impurities on the rate of the process under study. The values of the exchange current and transfer coefficient for silver reduction from TU solutions have been determined using this technique. Impurities in acid TU solution substantially increase the reduction rate for potentials more positive than about -0.5 V vs. Ag/AgCl.

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“…The electrochemical behavior of FDS has been studied in connection with that of thiourea [2,[8][9][10][11].…”

mentioning

confidence: 99%

On the electrochemical behavior of formamidine disulfide on gold electrodes in acid media

Cheuquepán

Orts

Rodes

2016

Journal of Electroanalytical Chemistry

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Please cite this article as: William Cheuquepán, José Manuel Orts, Antonio Rodes, On the electrochemical behavior of formamidine disulfide on gold electrodes in acid media, Journal of Electroanalytical Chemistry (2016Chemistry ( ), doi: 10.1016Chemistry ( /j.jelechem.2016 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.A C C E P T E D M A N U S C R I P T ACCEPTED MANUSCRIPT ABSTRACTThe adsorption and reactivity of formamidine disulfide (FDS) was studied at gold single crystal and thin film electrodes in perchloric acid solutions and the results of cyclic voltammetry and in situ infrared spectroscopy (SNIFTIR and ATR-SEIRAS) experiments compared with those previously obtained with thiourea (TU). In addition, optimized geometries and theoretical harmonic vibrational frequencies were obtained for adsorbed FDS, TU and thioureate from plane-wave DFT calculations using periodic surface models. These results were compared in the case of TU and thioureate to those previously obtained with a model Au cluster surface with (111) orientation. In the case of FDS, weak adsorption takes place with the S-S bond essentially parallel to the metal surface. No specific bands for adsorbed FDS can be identified in the experimental ATR-SEIRA spectra. These latter spectra suggest that adsorbed thioureate species are spontaneously formed upon dissociative adsorption of FDS when dosing this molecule at open circuit. Some of the adsorbed thioureate species undergo reductive protonation giving rise to a mixed adlayer formed by adsorbed thioureate and thiourea in a surface process which is faster when a controlled potential of 0.70 V is applied. In agreement with the observations reported when dosing TU, the ratio between TU and thioureate adsorbates is found to depend on the electrode potential, being higher for potentials close to the hydrogen evolution limit and decreasing for higher potential values. A C C E P T E D M A N U S C R I P T ACCEPTED MANUSCRIPT2 Graphical AbstractHighlights -FDS adsorbs weakly on Au with Au-S distances longer than those for TU and thioureate.-Physisorbed FDS dissociates homolitically to yield adsorbed thioureate.-Some adsorbed thioureate species are reduced to adsorbed thiourea.-Dosing conditions influence the rate of formation of adsorbed thiourea.-The thiourea/thioureate adsorbate ratio depends on the applied potential.

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

Cited by 38 publications

References 49 publications

Amperometric determination of thiourea in alkaline media on a copper oxide–copper electrode

Amperometric determination of thiourea in alkaline media on a copper oxide–copper electrode

Using an electrode with renewable surface for study of silver reduction from acid thiourea solutions

On the electrochemical behavior of formamidine disulfide on gold electrodes in acid media

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