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

Brimaud, Sylvain; Jusys, Z.; Behm, R. J.

doi:10.1007/s12678-011-0040-7

Cited by 8 publications

(12 citation statements)

References 46 publications

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“…In any case, all voltammograms display signal at 0.12, 0.27 and 0.37 V vs RHE which, as discussed in previous contributions [32,33], are related to the presence of (110) sites, (100) steps and terrace borders and (100) terraces or wide domains. Similar voltammetric profiles were also obtained with cubic Pt nanoparticles prepared with different synthetic approaches [30,[35][36][37][38][39][40][41][42][43], pointing out the presence of a (100) preferential surface structure. Interestingly, the characteristic voltammetric feature at about 0.5 V, due to the presence of (111) wide surface domains, is nearly negligible, even in the Pt (100 %), thus denoting the virtual absence of this type of surface structure on these Pt nanoparticles.…”

Section: Electrochemical Experimentssupporting

confidence: 70%

Influence of the metal loading on the electrocatalytic activity of carbon-supported (100) Pt nanoparticles

Vidal‐Iglesias

Montiel

Solla-Gullón

2015

J Solid State Electrochem

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The influence of the metal loading (i.e. interparticle distance) of shape-controlled Pt nanoparticles on their electrocatalytic properties is evaluated for the first time. For this purpose, carbon-supported cubic Pt nanoparticles (~17 nm) with different metal loadings were prepared, characterized and electrochemically tested. To avoid differences in particle size and shape/surface structure of the Pt nanoparticles between samples, all samples used in this work were prepared from a single batch. The surface structure of the Pt nanoparticles was evaluated through the so-called hydrogen region and showed a preferential (100) orientation. Interestingly, the electroactive surface area of the samples, estimated both from the H or CO stripping processes, was directly proportional to the total Pt mass, independently of the metal loading. The CO stripping profile was also found to be unaffected by the metal loading. However, for ammonia and formic acid electrooxidation, the activity obtained was dependent on the metal loading. For ammonia oxidation, the optimal loading was found to be about 20-30 wt%. Nevertheless, this trend may be altered by different factors including (i) active surface area, (ii) metal loading and (ii) thickness of the catalytic layer. For formic acid electrooxidation, the results obtained showed a clear decrease of the activity for increasing metal loadings which is explained in terms of formic acid consumption on the top layers of the catalyst.

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Section: Electrochemical Experimentssupporting

confidence: 70%

Influence of the metal loading on the electrocatalytic activity of carbon-supported (100) Pt nanoparticles

Vidal‐Iglesias

Montiel

Solla-Gullón

2015

J Solid State Electrochem

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“…The absence of a COad induced poisoning on Au electrodes agrees well with findings in in situ IR measurements, which did not detect any COad on the surface [4] . For completeness it should be noted, however, that this experimental finding does not rule out the formation and instantaneous desorption of CO during HCOOH oxidation, since COad is not irreversibly adsorbed on Au [19][20][21] . Similar measurements were performed for various pH values below and above the pKa of HCOOH on a polycrystalline Au bead (Fig.…”

Section: Effect Of Electrolyte Ph On Hcooh Electro-oxidationmentioning

confidence: 81%

Formic Acid Electrooxidation on Noble‐Metal Electrodes: Role and Mechanistic Implications of pH, Surface Structure, and Anion Adsorption

et al. 2014

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We have investigated the influence of the electrolyte pH on formic acid (HCOOH) electro-oxidation on both polycrystalline Pt and Au electrodes, and on single-crystalline Au electrodes in perchloric and sulphuric acid based electrolytes. On Au electrodes, the potentiodynamic oxidation currents are found to depend in a nonlinear way on the electrolyte pH, in a bell-shaped relation with a maximum of the catalytic activity at the pKa of HCOOH. On polycrystalline Pt electrodes, this feature is not observed and the catalytic activity increases steadily with increasing pH up to pH ≈ 5 followed by a plateau until pH 10, in contrast with recent observations [T. Joo et al., J. Amer. Chem. Soc., 135 (2013) 9991]. In addition, for Au surfaces, the reaction is only weakly influenced by the electrode surface structure, while for Pt structural effects are known to be considerable. Anion effects, in contrast, are much stronger for reaction on Au than for Pt electrodes. Also, it is shown that Pt group metal free Au electrodes do not oxidize molecular hydrogen under reaction conditions. The results are discussed in relation to findings in previous mechanistic studies. Most important, the activity is on both electrodes closely correlated with the concentration of HCOO -anions, for Au with both HCOO -and HCOOH concentrations. Based on these results, a number of mechanistic proposals put forward in earlier studies must be discarded, examples for mechanisms compatible with these results are discussed.

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“…A more detailed description of this flow-cell configuration was previously given in [31]. In brief, the central cell Au film was prepared by electroless deposition following the procedure reported previously [32][33][34]. It has to be thin enough to allow the IR radiation to pass to the nanoparticles, but thick enough to be sufficiently conductive for obtaining a good electrochemical response.…”

Section: Methodsmentioning

confidence: 99%

Ethanol oxidation on shape-controlled platinum nanoparticles at different pHs: A combined in situ IR spectroscopy and online mass spectrometry study

Busó-Rogero

Brimaud

Sollá-Gullón

et al. 2016

Journal of Electroanalytical Chemistry

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Ethanol oxidation on different shape-controlled platinum nanoparticles at different pHs was studied using electrochemical, Attenuated Total Reflection -Fourier Transform Infrared Spectroscopy (ATR-FTIR) and, especially, Differential Electrochemical Mass Spectrometry (DEMS) techniques, which gives interesting quantitative information about the products of ethanol oxidation. Two Pt nanoparticle samples were used for this purpose: (100) and (111) preferentially oriented Pt nanoparticles. The results are in agreement with previous findings that the preferred decomposition product depends on surface structure, with COads formation on (100) domains and acetaldehyde/acetic acid formation on (111) domains. However, new information has been obtained about the changes in CHx and CO formation at lower potentials when the pH is changed, showing that CHx formation is favored against the decrease in CO adsorption on (100) domains. At higher potentials, complete oxidation to CO2 occurs from both CHx and CO fragments. In (111) Pt nanoparticles, the splitting of C-C bond is hindered, favoring acetaldehyde and acetate formation even in 0.5 M H2SO4. C1 fragments become even less when the pH increases, being nearly negligible in the highest pH studied.

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

Cited by 8 publications

References 46 publications

Influence of the metal loading on the electrocatalytic activity of carbon-supported (100) Pt nanoparticles

Influence of the metal loading on the electrocatalytic activity of carbon-supported (100) Pt nanoparticles

Formic Acid Electrooxidation on Noble‐Metal Electrodes: Role and Mechanistic Implications of pH, Surface Structure, and Anion Adsorption

Ethanol oxidation on shape-controlled platinum nanoparticles at different pHs: A combined in situ IR spectroscopy and online mass spectrometry study

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