ChemInform Abstract: MECHANISMUS DER OX. VON AETHYLEN AN EINER GLATTEN GOLDELEKTRODE

Michri, A. A.; Pshenichnikov, A. F.; Burshtein, R. Kh.

doi:10.1002/chin.197229109

Cited by 34 publications

(45 citation statements)

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“…The apparent surface area of the working electrode was 0.63 cm 2 . The surface roughness factor k of sputtered gold layer evaluated according to Burshtein method [17] was about 3. The gold underlayer was inert under the conditions of experiment [18,19].…”

Section: Methodsmentioning

confidence: 99%

EQCM Study of Ru and RuO₂ Surface Electrochemistry

Juodkazytė¹,

Vilkauskaitė²,

Stalnionis³

et al. 2007

Electroanalysis

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The present study represents comparative analysis of voltammetric and microgravimetric behavior of active ruthenium (Ru), electrochemically passivated ruthenium (Ru/RuO 2 ) and thermally formed RuO 2 electrodes in the solutions of 0.5 M H 2 SO 4 and 0.1 M KOH. It has been found that cycling the potential of active Ru electrode within E ranges 0 V -0.8 V and 0 V -1.2 V in 0.5 M H 2 SO 4 and 0.1 M KOH solutions, respectively, leads to continuous electrode mass increase, while mass changes observed in alkaline medium are considerably smaller than those in acidic one. Microgravimetric response of active Ru electrode in 0.5 M H 2 SO 4 within 0.2 V -0.8 V has revealed reversible character of anodic and cathodic processes. The experimentally found anodic mass gain and cathodic mass loss within 0.2 -0.8 V make 2.2 -2.7 g F À1 , instead of 17 g F À1, which is the theoretically predicted value for Ru(OH) 3 formation according to equationIn the case of Ru/RuO 2 electrode relatively small changes in mass have been found to accompany the anodic and cathodic processes within E range between 0.4 V and 1.2 V in the solution of 0.5 M H 2 SO 4 . Meanwhile cycling the potential of thermally formed RuO 2 electrode under the same conditions has lead to continuous decrease in electrode mass, which has been attributed to irreversible dehydration of RuO 2 layer. On the basis of microgravimetric and voltammetric study as well as the coulometric analysis of the results conclusions are presented regarding the nature of surface processes taking place on Ru and RuO 2 electrodes.

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Section: Methodsmentioning

confidence: 99%

EQCM Study of Ru and RuO₂ Surface Electrochemistry

Juodkazytė¹,

Vilkauskaitė²,

Stalnionis³

et al. 2007

Electroanalysis

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“…The surface roughness factor of gold-plated sandblasted titanium, evaluated according to Burshtein method [33], was about 18.…”

Section: Methodsmentioning

confidence: 99%

Iridium Anodic Oxidation to Ir(III) and Ir(IV) Hydrous Oxides

et al. 2005

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Iridium oxide films (IROFs) are known to have an enhanced or the so-called super-Nernstian (< 59 mV/pH) pHsensitivity. The intention in the present study was to find out the reasons of such behavior and also to elucidate the nature of iridium anodic oxidation processes. The methods employed were combined cyclic voltammetry and chronopotentiometry. Iridium layers of 0.1 to 0.2 mm thickness, deposited thermally on titanium or gold-plated titanium substrates, were used for investigations. IROFs on the surface of working electrodes were formed anodically by applying a constant potential in deaerated and oxygen-containing solutions of 0.5 M H 2 SO 4 , 0.1 M KOH and 0.5 M H 3 PO 4 þ KOH. Linear pH-dependences of the stationary open-circuit potential with the slopes close to 59 mV/pH were found for iridium electrode oxidized at 0.4 V -0.8 V (RHE) in deaerated and at 0.8 V -1.2 V (RHE) in O 2 -containing solutions. They were attributed to reversible Ir/Ir(OH) 3 and Ir/ IrO 2 · nH 2 O metal-oxide electrodes, respectively. It has been suggested that the main current peaks seen in the voltammograms of iridium electrode in acid and alkaline solutions are of different nature. The difference between iridium electrode surface states in acid and alkaline solutions has been presumed to be the main reason of super-Nernstian pH-sensitivity of the IROFs. On the basis of the results obtained standard potential of Ir/Ir(OH) 3 electrode and the solubility product of Ir(OH) 3 have been evaluated: E Ir=IrðOHÞ 3 ¼ 0.78 AE 0.02 V and K sp ¼ 3.3 Â 10 À64 .

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“…AT-cut quartz crystal of 6 MHz fundamental frequency (Intelemetrics Ltd., UK) sputtered with gold on both sides was used. The surface roughness factor k of sputtered gold layer evaluated according to Burshtein method [25] was about 3. On the one side of the quartz crystal electrode a layer of iridium (0.1 -0.2 mm) was formed by means of thermal decomposition of H 2 IrCl 6 solution at 400 8C in argon atmosphere.…”

Section: Methodsmentioning

confidence: 99%

EQCM Study of Iridium Anodic Oxidation in H₂SO₄ and KOH Solutions

et al. 2005

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In the present study anodic oxidation of iridium layer formed thermally on a gold-sputtered quartz crystal electrode has been investigated by electrochemical quartz crystal microgravimetry (EQCM) in the solutions of 0.5 M H 2 SO 4 and 0.1 M KOH. The emphasis here has been put on the microgravimetric behavior of iridium as a metal, because a few previous EQCM studies reported in literature have been devoted to iridium oxide films (IROFs). The objective pursued here has been to elucidate the nature of the main voltammetric peaks, which occur at different ranges of potential in the solutions investigated. It has been found that anodic oxidation of iridium electrode in 0.5 M H 2 SO 4 and 0.1 M KOH solutions is accompanied by irregular fluctuations of the electrode mass at 0.4 V < E < 0.8 V followed by regular increase in mass at 0.8 V < E < 1.2 V. The cathodic process initially, at 1.2 V > E > 0.9 V, proceeds without any or with slight increase in electrode mass, whereas at E < 0.8 V a regular decrease in mass is observed. It has been found that mass to charge ratio characterizing the processes of interest is 2 to 3 g F À1 in acidic medium, whereas in the case of alkaline one it is 4 to 6 g F À1. The main pair of peaks seen in the voltammograms of Ir electrode in alkaline medium at E < 0.8 V is attributable to redox transition Ir(0) ! Ir(III), whereas those observed in the case of acidic medium at E > 0.8 V should be related to the redox process Ir(0) ! Ir(IV) going via intermediate stage of Ir(III) formation. As a consequence of these redox transitions, the gel-like surface layer consisting of Ir(III) or Ir(IV) hydrous oxides forms on the electrode surface.

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ChemInform Abstract: MECHANISMUS DER OX. VON AETHYLEN AN EINER GLATTEN GOLDELEKTRODE

Cited by 34 publications

References 0 publications

EQCM Study of Ru and RuO₂ Surface Electrochemistry

EQCM Study of Ru and RuO₂ Surface Electrochemistry

Iridium Anodic Oxidation to Ir(III) and Ir(IV) Hydrous Oxides

EQCM Study of Iridium Anodic Oxidation in H₂SO₄ and KOH Solutions

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ChemInform Abstract: MECHANISMUS DER OX. VON AETHYLEN AN EINER GLATTEN GOLDELEKTRODE

Cited by 34 publications

References 0 publications

EQCM Study of Ru and RuO2 Surface Electrochemistry

EQCM Study of Ru and RuO2 Surface Electrochemistry

Iridium Anodic Oxidation to Ir(III) and Ir(IV) Hydrous Oxides

EQCM Study of Iridium Anodic Oxidation in H2SO4 and KOH Solutions

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EQCM Study of Ru and RuO₂ Surface Electrochemistry

EQCM Study of Ru and RuO₂ Surface Electrochemistry

EQCM Study of Iridium Anodic Oxidation in H₂SO₄ and KOH Solutions