Correlação entre a estrutura atômica superficial e o processo de adsorção-dessorção reversível de hidrogênio em eletrodos monocristalinos Pt(111), Pt(100) e Pt(110)

Santos, Vagner Bezerra dos; Filho, Germano Tremiliosi

doi:10.1590/s0100-40422001000600024

Cited by 28 publications

(16 citation statements)

References 26 publications

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“…5f, it is clearly observed that the cleavage of ethanol molecule to form adsorbed CO linear occurs on Pt (110) (nonmodified and modified electrode) at lower potentials than on Pt(111) and Pt(100). This could be an influence of the well-known highly stepped (110) face [48]. The intensity of the CO linear band reaches a maximum value at approximately 0.4 V for the intermediary osmium coverage degree studied (θ Os =0.51), different from those observed for Pt(111)/Os and Pt(100)/Os, which show the best performance to form adsorbed CO at lower osmium coverages.…”

Section: Pt(110)/osmentioning

confidence: 67%

“…1c), the modification by low coverages of Os did not diminish the hydrogen adsorptiondesorption peaks at the 0.1-03 V region, different from the observed behavior for Pt(100) and Pt(111). This feature can be a consequence of the less compact surface structure of Pt (110), the most highly stepped face of platinum [48]. When higher amounts of Os is added to this surface (coverage degree above 0.51), the significant diminishing of the peak at 0.1-03 V is accompanied by a high increase of the current at lower potentials (0.1-0.15 V), which is attributed to a significant increase in the capacitive CV currents.…”

Section: Voltammetric Studiesmentioning

confidence: 99%

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Comparative Electrochemical and Spectroscopic Studies of Ethanol Oxidation on Pt(h,k,l) Modified by Osmium Nanoislands

2010

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This work reports the electrochemical and spectroscopic studies of ethanol electrooxidation on the platinum single-crystal electrodes (111, 100, 110) surface-modified by different coverage degrees of osmium. In general, after deposition of osmium (θ Os =0.40-0.50), an increase in the voltammetric current of ethanol oxidation was observed, indicating an enhancement of the catalytic activity of the electrode. According to Fourier transformed infrared results, the mechanistic pathway for this reaction depends directly on the degree of osmium coverage. Thus, for low osmium coverage (θ Os <0.20), the formation of CO as an intermediate is favored, giving CO 2 as the main final product; for intermediate osmium coverage (θ Os =0.25-0.50), the acetaldehyde formation is enhanced; and for higher osmium coverage (θ Os >0.92), the catalytic activity for ethanol oxidation tends to decrease, producing insignificant amounts of CO and CO 2 . Moreover, at this surface, the direct oxidation of ethanol to acetic acid (pathway not interesting for energetic ends) is also observed at lower potentials.

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Section: Pt(110)/osmentioning

confidence: 67%

Section: Voltammetric Studiesmentioning

confidence: 99%

Comparative Electrochemical and Spectroscopic Studies of Ethanol Oxidation on Pt(h,k,l) Modified by Osmium Nanoislands

2010

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“…present in the solution and the adsorbed hydrogen oxidation. In these regions of potential, the superficial arrangement of the atoms is of fundamental importance since they present a different hydrogen adsorption energy and are used to determine the electrochemical active area [20].…”

Section: Resultsmentioning

confidence: 99%

Sn@Pt and Rh@Pt core–shell nanoparticles synthesis for glycerol oxidation

et al. 2014

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The development and optimization of electrocatalysts for application in fuel cell systems have been the focus of a variety of studies where core-shell structures have been considered as a promising alternative among the materials studied. We synthesized core-shell nanoparticles of Sn x @Pt y and Rh x @Pt y (Sn@Pt, Sn@Pt 2 , Sn@Pt 3 , Rh@Pt, Rh@Pt 2 , and Rh@Pt 3 ) through a reduction methodology using sodium borohydride. These nanoparticles were electrochemically characterized by cyclic voltammetry and further analyzed by cyclic voltammetry studying their catalytic activity toward glycerol electro-oxidation; chronoamperometry and potentiostatic polarization experiments were also carried out. The physical characterization was carried out by X-ray diffraction, energy-dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy, and transmission electron microscopy. The onset potential for glycerol oxidation was shifted in 130 and 120 mV on the Sn@Pt 3 /C and Rh@Pt 3 /C catalysts, respectively, compared to commercial Pt/C, while the stationary pseudo-current density, taken at 600 mV, increased 2-fold and 5-fold for these catalysts related to Pt/C, respectively. Thus, the catalysts synthesized by the developed methodology have enhanced catalytic activity toward the electro-oxidation of glycerol, representing an interesting alternative for fuel cell systems.

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“…5, it is clearly observed that the cleavage of the C-C bond of the ethanol molecule to form adsorbed CO linear occurs on Pt(110) (unmodified and modified electrode) in potentials as low as 0.2 V. This could be an influence of the well-known highly stepped (110) face [28]. The intensity of the CO linear band reaches a maximum value at approximately 0.4 V for a range of osmium coverage degrees between 0.36 and 0.80 ML.…”

Section: In Situ Ftir Studies Of Ethanol and Acetaldehyde Oxidation Omentioning

confidence: 98%

Electrochemical and Spectroscopic Studies of Ethanol and Acetaldehyde Oxidation Onto Pt(110) Modified by Osmium

Colle

Tremiliosi‐Filho

2011

Electrocatal

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This paper presents the studies of ethanol and acetaldehyde electrooxidation onto Pt(110) electrode modified by different osmium coverage. These oxidation reactions were studied by in situ Fourier transform infrared spectroscopy. It was shown that the catalytic activity of Pt (110) after osmium deposition for ethanol oxidation is greater than that observed on unmodified Pt(110). It was also demonstrated that the mechanistic pathway for this reaction depends directly on the degree of osmium coverage. Thus, for low osmium coverage (θ Os ≤0.12), the formation of CO and CO 2 is not so effective when compared with other coverage degrees, and hence the full oxidation of adsorbed ethanol to CO 2 is increased when the Os is deposited in the range of 0.30-0.80 ML. Additionally, the formation of acetaldehyde is also observed in low degree of osmium coverage. For a complete osmium layer (θ Os >1.0), the catalytic activity of the electrode for ethanol oxidation shows the lowest value. The acetaldehyde oxidation reaction on Pt(110)/Os favors the CO 2 production. For electrodes covered completely by Os layer, a considerable presence of CO 2 above 0.8 V was observed; in contrast with the very low quantity of adsorbed CO linear , this suggests that the CO 2 can also be formed from the oxidation of a possible strongly adsorbed species at high potentials on this surface, or it can also be considered that acetaldehyde can be oxidized to CO 2 by the cleavage of C-C bond.

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Correlação entre a estrutura atômica superficial e o processo de adsorção-dessorção reversível de hidrogênio em eletrodos monocristalinos Pt(111), Pt(100) e Pt(110)

Cited by 28 publications

References 26 publications

Comparative Electrochemical and Spectroscopic Studies of Ethanol Oxidation on Pt(h,k,l) Modified by Osmium Nanoislands

Comparative Electrochemical and Spectroscopic Studies of Ethanol Oxidation on Pt(h,k,l) Modified by Osmium Nanoislands

Sn@Pt and Rh@Pt core–shell nanoparticles synthesis for glycerol oxidation

Electrochemical and Spectroscopic Studies of Ethanol and Acetaldehyde Oxidation Onto Pt(110) Modified by Osmium

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