An FTIR study of adsorbed sulfate species on polycrystalline platinum with application of group theory to the problem of band assignment for adsorbed species

Nart, Francisco Carlos; Iwasita, T.

doi:10.1016/0022-0728(92)80083-g

Cited by 69 publications

(33 citation statements)

References 14 publications

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“…Cyclic Voltammetry (CV) analyses were performed with a Autolab (Ecochemie model Though there is known that electrolytes like phosphate and sulfate adsorb on the surface of platinum [19,20], our results indicate that the electrochemical response of electrooxidation of GHB is not appreciably dependent on the nature of the electrolyte and, thus, the GHB molecules adsorb to the platinum surface from the first contact at negative potentials. This is evidenced by the important suppression of the hydrogen adsorption/desortion peaks in the lower potential region.…”

Section: Methodsmentioning

confidence: 85%

Electrochemical behaviour of gamma hydroxybutyric acid at a platinum electrode in acidic medium

Jiménez‐Pérez

Sevilla

Pineda

et al. 2013

Electrochimica Acta

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Abstract.Gamma Hydroxybutyric Acid (GHB), when studied in a platinum electrode using cyclic voltammetry, presented three oxidation peaks in acid solutions that correspond to the oxidation of the alcohol group to the corresponding aldehyde and carboxylic acid (succinic acid). An anodic scan of GHB yielded two characteristic waves, which indicates an oxidation process dependent on the chemical environment on the surface of the electrode. The cathodic scan presented an inverted oxidation peak with an onset partially overlapping with the tail of the cathodic peak for the reduction of the platinum oxide formed initially during the anodic scan. This inverted peak can be observed at a potential close to +0.2V (vs Ag/AgCl at pH 2) and separated 0.4 and 0.8 V from the two other oxidation peaks obtained during the anodic scan and in such conditions that the surface is particularly activated to favour this electrochemical process. The response obtained in the electronic current for the different peaks when GHB concentration and scan rate were changed allows inferring that these are the result of a potential dependent mechanism.

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Section: Methodsmentioning

confidence: 85%

Electrochemical behaviour of gamma hydroxybutyric acid at a platinum electrode in acidic medium

Jiménez‐Pérez

Sevilla

Pineda

et al. 2013

Electrochimica Acta

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“…The contribution of HSO 4 -during the oxidation of aniline in H 2 SO 4 solution can be confirmed from two downward bands at 1190 and 1053 cm -1 , which are assigned to the asymmetric (1195 cm -1 ) and symmetric (1050 cm -1 ) stretching vibrations of HSO 4 -. 17,18 These bands were attended by an upward peak at 1105 cm -1 , attributable to SO 4 2-.…”

Section: Polymerization In H 2 So 4 Solutionmentioning

confidence: 97%

In Situ Observation of Electrochemical Formation and Degradation Processes of Polyaniline by Fourier-Transform Infrared Spectroscopy

1999

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Polyaniline (PAn) is an electrically conducting polymer that can be easily prepared by the chemical and electrochemical oxidation of aniline, and shows excellent stability under ambient conditions. Electrochemical synthesis is generally carried out on metal electrodes in aqueous acidic solutions, such as HClO 4 , HCl and H 2 SO 4 , using potentiostatic, galvanostatic and potential cycling methods. A large number of studies on the redox process of PAn have been performed by means of electrochemical and optical techniques, revealing that electron transfer causes the migration of electrolyte ions into or out of the polymer film. 1 However, the scheme of electropolymerization of aniline, involving the charge-compensation manner, is not well understood. A film prepared from HClO 4 is known to be denser than that from H 2 SO 4 , suggesting that the electrolyte anion plays an important role in the polymerization of aniline. 2,3 According to the reaction scheme proposed by Mohilner et al., polymerization starts by the oxidation of non-protonated aniline to radical cationic species, and proceeds through coupling with another radical; these reactions are accompanied by the release of protons to eliminate the generated positive charges. 4 This suggests that the acidity at the polymer/solution interface increases during the course of aniline oxidation, but the effect of accumulated protons on the rate of polymerization is not determined. Furthermore, side reactions, such as degradation of the polymer, are not negligible during prolonged polymerization. 5 An in situ spectroelectrochemical method is useful to study such unclear problems.In the present study, in situ FTIR spectroscopy was applied to the electrochemical polymerization of aniline, and the growing polymer and polymer/solution interface were investigated on the molecular level. In situ FTIR spectroscopy has proven to be fruitful for studies on the metal/solution interface 6 and an electroactive film.7 An advantage of this technique when used in the latter system is that it allows a simultaneous determination of the polymer structure and movement of electrolyte species through the film. ExperimentalAll chemicals were of reagent grade and used as received. Sulfuric and perchloric acid solutions used as the electrolytes were prepared with those chemicals and doubly distilled water, and higher pH values were adjusted by adding a concentrated NaOH solution.The FTIR spectrometer used was a Shimadzu FTIR 8100M equipped with an external-reflection unit and a HgCdTe (MCT) detector cooled with liquid nitrogen. The spectroelectrochemical cell was similar to that described elsewhere. 8 A flat CaF 2 disk was used as the IR transparent window, and the angle of incidence on the CaF 2 surface was 70˚. Spectroelectrochemical experiments were carried out with a Pt disk (area=0.50 cm 2 ) substrate. The Pt surface was polished to a mirror finish with 0.3 µm alumina paste and sonicated for 10 The electrochemical polymerization of aniline on a platinum electrode in aqueous HClO4 and H...

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“…They exhibit two negative bands at ∼1,260 and ∼1,120 cm −1 for nc-Pt and two positive bands at ∼1,250 and ∼1,120 cm −1 for the pc-Pt film. These are assigned to adsorbed (bi) sulfate anions (reference spectrum was recorded at 100 mV on the CO-covered Pt surface) [44,45]. Also here, the polarity of the (bi)sulfate IR bands is reversed on the nc-Pt sample.…”

Section: Adlayer Vibrational Propertiesmentioning

confidence: 99%

Controlled Surface Structure for In Situ ATR-FTIRS Studies Using Preferentially Shaped Pt Nanocrystals

2011

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We explored the possibility of using preferentially shaped Pt nanocrystals deposited on a gold film for in situ Fourier transform infrared spectroscopy (FTIRS) studies in an attenuated total reflection (ATR) configuration as Pt electrodes with a well-defined ordered surface structure. Hydrogen region voltammograms as well as characteristic bands of adsorbed CO and (bi) sulfate resolve surface structure-specific features consistent with previously published infrared reflection absorption spectroscopic studies on similarly structured low index single crystalline Pt electrodes, supporting the validity of this approach.

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An FTIR study of adsorbed sulfate species on polycrystalline platinum with application of group theory to the problem of band assignment for adsorbed species

Cited by 69 publications

References 14 publications

Electrochemical behaviour of gamma hydroxybutyric acid at a platinum electrode in acidic medium

Electrochemical behaviour of gamma hydroxybutyric acid at a platinum electrode in acidic medium

In Situ Observation of Electrochemical Formation and Degradation Processes of Polyaniline by Fourier-Transform Infrared Spectroscopy

Controlled Surface Structure for In Situ ATR-FTIRS Studies Using Preferentially Shaped Pt Nanocrystals

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