Dependence of the electrooxidation rates of carbon monoxide at gold on the surface crystallographic orientation: a combined kinetic-surface infrared spectroscopic study

Chang, Si Chung; Hamelin, A.; Weaver, Michael J.

doi:10.1021/j100167a037

Cited by 90 publications

(102 citation statements)

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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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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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“…[32] The bulk oxidation of carbon monoxide on the nanoparticles did not show surface-structure sensitivity,w hich is in agreement with results described previously in the literature. [22,31,54] Figures 3A and Bs how the voltammetric profiles of methanol and formaldehyde on the cubic and octahedral Au nanoparticles in alkaline medium. For methanol, as can be seen in Figure3A, the voltammetric profiles are quite similar,b oth in terms of the onset of the oxidation( ca.…”

Section: Electrochemical Oxidation Of Carbonm Onoxide Methanol and mentioning

confidence: 99%

“…0.3 Vv s. RHE), the current densities obtained on the (111)p referentially oriented nanoparticles are, in both cases, highera t low potentials( up to 0.95 V), whereas the Au cubic nanoparticles are more active at potentials higher than 1.0 V. Previous FTIR measurements have indicatedt hat formate is the final product of the oxidation of formaldehyde when the potential is limited to 1.5Vand cannot be furtheroxidized. [29,31,54,55] …”

Section: Electrochemical Oxidation Of Carbonm Onoxide Methanol and mentioning

confidence: 99%

Electrochemical Oxidation of Small Organic Molecules on Au Nanoparticles with Preferential Surface Orientation

et al. 2015

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The surface orientation effect on the oxidation of small organic molecules such as methanol, formaldehyde, ethanol, and glycerol has been studied on Au nanoparticles in alkaline medium. Two sets of Au nanoparticles enriched in (100) and (111) facets were synthetized by using colloidal methods in presence of cetyltrimethylammonium bromide. The nanoparticles were physically characterized by using TEM and XRD and electrochemically characterized by using Pb underpotential deposition as a surface‐structure probe. It is reported that, although methanol oxidation was similar in both types of nanoparticles, the oxidation of formaldehyde presented a clear surface orientation effect. For this reaction, nanoparticles with (111) preferential orientation presented higher current densities at low potentials, whereas Au(100) nanoparticles exhibited higher activity at potentials more positive than 1.0 V versus RHE. On the other hand, for glycerol and ethanol oxidations, the onset of the reaction was similar in both types of particles, although Au(111) nanoparticles showed higher current densities than the Au(100) ones.

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“…[17][18][19][20] for reviews). While the majority of these infrared spectroscopic studies have examined CO adsorption at the low index surface planes of platinum and rhodium, similar experiments using well-ordered high index surface planes of single crystal electrodes have recently appeared [3,4,[21][22][23], and work with Pt(335)/CO is the first of these to observe specific site-dependent phenomena [3,4].…”

Section: Introductionmentioning

confidence: 99%

Site-dependent vibrational coupling of CO adsorbates on well-defined step and terrace sites of monocrystalline platinum: Mixed-isotope studies at Pt(335) and Pt(111) in the aqueous electrochemical environment

Kim

Tornquist

Korzeniewski

1994

The Journal of Chemical Physics

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Infrared spectroscopy is applied to probe qualitative structural features of the adlayers formed by CO at step sites and on terrace planes of Pt(335){Pt(S)-[4(111)×(100)]} in the aqueous electrochemical environment. The C–O stretching vibrational features are reported for adlayers formed from 12CO/13CO isotopic mixtures over a wide range of CO surface coverages. At saturation, the predominant spectral features are associated with the vibrational modes of terrace-CO in terminal (atop) coordination environments. The position of the 12CO and 13CO spectral features and their relative intensity are examined for several 12CO/13CO fractions, and they are shown to display the characteristics of a strongly coupled system. In comparison with corresponding mixed isotope spectra for CO at Pt(111) electrodes, intermolecular coupling for terrace-CO on the (111) surface planes of Pt(335) is observed to be significantly stronger, reflecting the higher CO surface coverages on the edge sites and the terrace sites of the Pt(335) surface plane. At low coverages, spectral features associated with edge-CO are discerned, and the intermolecular coupling for atop CO is weaker than for corresponding coverages of CO at Pt(111). The weak coupling at low coverages is attributed to the exclusive CO occupation at the step edges, which confines the intermolecular coupling to one dimension, in the direction along the step edges. For all coverages, values are determined for the dynamic dipole–dipole coupling parameter (Δνd) and the chemical (static–dipole) shift parameter (Δνs). Values for Δνs are generally small at all coverages. Values for Δνd are small (<8 cm−1) at low coverages, where CO forms one-dimensional structures along the step edges, and they increase to large values (∼42 cm−1) at coverages that coincide with the growth of two-dimensional structures on the terrace planes. The majority of measurements were made for the Pt(335) electrode at potentials in the classical double-layer region, although dipole coupling parameters are also reported for Pt(335)/CO at potentials in the hydrogen adsorption region, where Δνd approaches zero at low coverages.

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Dependence of the electrooxidation rates of carbon monoxide at gold on the surface crystallographic orientation: a combined kinetic-surface infrared spectroscopic study

Cited by 90 publications

References 0 publications

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

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

Electrochemical Oxidation of Small Organic Molecules on Au Nanoparticles with Preferential Surface Orientation

Site-dependent vibrational coupling of CO adsorbates on well-defined step and terrace sites of monocrystalline platinum: Mixed-isotope studies at Pt(335) and Pt(111) in the aqueous electrochemical environment

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