The voltammetric behaviour of H and O adatoms in the 189–292 K range on platinum in HClO4 · 5.5 H2O and H2SO4 · 12H2O

Florit, M.I.; Arvía, Alejandro Jorge

doi:10.1016/0022-0728(92)80458-g

Cited by 6 publications

(2 citation statements)

References 32 publications

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“…The effect of temperature on the kinetics of electrochemical reactions has been studied during the last decades, particularly to evaluate the temperature dependence of Tafel slopes and its relation to electron transfer theory [1]. More recently, the hydrogen electrode reaction (HER) on Pt in HC104 -5.5H20 in the range 189-292 K [2,3] and the voltammetric behaviour of H and O adatoms on Pt in HzSO 4 • 12H20 and HCIO 4 • 5.5H20 in the range 189-292 K [4,5] have received special consideration. Although restricted to Pt, these results are highly interesting when exploring new aspects related to the structure of the metal Isolution interface in relation to the kinetics of electrocatalytic processes.…”

Section: Introductionmentioning

confidence: 99%

Reactions involving H, OH and O species on rhodium in H2SO4·12H2O and HClO4·5.5H2O in the range 198–298 K

Florit

Bolzán

Arvía

1995

Journal of Electroanalytical Chemistry

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The voltammetric behaviour of polycrystalline rhodium in H2SO 4 • 12H20 and HCIO 4 • 5.5H20 was investigated by conventional and triangularly modulated voltammetry in the range 198-298 K. H and OH electrosorption reactions and a fast electrochemical process in the potential range preceding the oxygen evolution reaction (OER) were studied. For both electrolytes, as the temperature diminished, the H atom reactions and those reactions related to the O-containing surface species became increasingly irreversible, whereas the fast electrochemical process preceding the OER was nearly the same, irrespective of the temperature. Explanations recently advanced for the behaviour of Rh in more diluted solutions of the same acids at 298 K and the electrochemical behaviour of the different processes are discussed, considering mainly the effects of sulphate anion adsorption and perchlorate anion decomposition on Rh.

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Section: Introductionmentioning

confidence: 99%

Reactions involving H, OH and O species on rhodium in H2SO4·12H2O and HClO4·5.5H2O in the range 198–298 K

Florit

Bolzán

Arvía

1995

Journal of Electroanalytical Chemistry

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“…The experimental setup for the electrochemical measurements was a three-electrode glass electrochemical cell as described in Ref. 25. The working electrode was surrounded by a Pt foil which served as counter electrode.…”

Section: Methodsmentioning

confidence: 99%

The Effect of Temperature on the Impedance of Poly‐o‐toluidine in 3.7 M H 2 SO 4

Florit

Posadas

Molina

et al. 1999

J. Electrochem. Soc.

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Many aspects of the conduction mechanism and the electrochemical switching of arylamine-derived polymers are still under discussion. 1,2 Although a variety of techniques has been applied to the study of these problems, the effect of temperature has received little attention. [3][4][5][6][7][8] On the other hand, electrochemical impedance spectroscopy (EIS) has proved to be a powerful technique for studing the electrochemical behavior of this kind of polymers. Several impedance studies of poly(aniline) (PANI) have contributed 3,[9][10][11][12][13][14] to the present understanding of the charge-transport processes in this type of polymers. Recently, we have applied EIS to study the response of poly(otoluidine) (POT), [15][16][17][18][19] in both the insulating (reduced) 20 and the conducting (half-oxidized) 21 states; as well as to the insulator-conducting transition. 21 There, it is concluded that in the reduced state the conductivity at very high frequencies is independent of the conductivity of the bathing electrolyte and cannot be explained by the sole contribution of the solution within the polymer pores. Also, in the reduced state, the EIS response, which is characterized by a big semicircle, is due to ionic charge transfer across the polymer-solution interface. 20 On the other hand, in the conducting state, the high-frequency conductivity of the polymer is very high whereas at low frequencies it is lower and is controlled by the diffusion of anions in the polymer. 21 The conductivity of PANI has been studied as a function of temperature by Inzelt et al., 3 in the range 296 to 324 K, with the aim of differentiating the conceivable conduction mechanisms. Among other things it was found that the conductivity increases as the temperature rises. Moreover, in a recent paper 22 it has been reported that the in situ conductivity of PANI was found to increase in the range 278 to 348 K.Here, we show the impedance response of POT in 3.7 M H 2 SO 4 , as a function of temperature, in the range 218 to 293 K. Since we were interested in the insulator-conductor transition and in the properties of the insulating and conducting states, we have studied only the potential region corresponding to the first oxidation peak, in our case the range going from 0.0 to 0.6 V. ExperimentalThe POT films were built up on Au electrodes by electropolymerization of the monomer at room temperature, from 0.65 M o-toluidine ϩ 1.5 M H 2 SO 4 ϩ 1.5 M HClO 4 solution, by continuously cycling the potential at 0.1 V s Ϫ1 , between 0.15 and 0.95 V vs. reference hydrogen electrode (RHE). 19 The film thicknesses were derived from the voltammetric charges in free monomer electrolyte (Q ϭ 13 mC cm Ϫ2 ). On the basis of the relationship between the reduction charge and the film thickness, which was previously established by ellipsometry for similar polymers, 23,24 the polymer thickness is about 62 nm. The electrolyte solutions were prepared from H 2 SO 4 (97%), HClO 4 (70%) acids [Merck, purified agent (p.a.)], o-toluidine (Fluka-Garantie, puriss. p.a.), a...

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Formation and reduction of hydrous oxide films on platinum in aqueous solution at 273 K

Burke¹,

Buckley²

1995

J Appl Electrochem

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The voltammetric behaviour of H and O adatoms in the 189–292 K range on platinum in HClO4 · 5.5 H2O and H2SO4 · 12H2O

Cited by 6 publications

References 32 publications

Reactions involving H, OH and O species on rhodium in H2SO4·12H2O and HClO4·5.5H2O in the range 198–298 K

Reactions involving H, OH and O species on rhodium in H2SO4·12H2O and HClO4·5.5H2O in the range 198–298 K

The Effect of Temperature on the Impedance of Poly‐o‐toluidine in 3.7 M H 2 SO 4

Formation and reduction of hydrous oxide films on platinum in aqueous solution at 273 K

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