An infrared study of CO adsorption on Pt(111)

Olsen, Charles; Masel, Richard I.

doi:10.1016/0039-6028(88)90496-7

Cited by 110 publications

(86 citation statements)

References 26 publications

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“…It is of interest to note that, in UHV, 12 CO dilution limit frequencies for Pt( 111)/CO follow a different coverage dependent trend [31,32]. The difference is attributable to the platinum surface potential, which is considerably more negative in the electrochemical environment than in UHV.…”

Section: Mixed Isotope Experiments On Saturated Co Adlayersmentioning

confidence: 99%

“…We also estimated the terrace-CO singleton value using the dilution limit frequency measured in the low coverage limit for terrace-CO (at 0 / 0 max = 0.3) [27,31,32,35]. This latter approach gives a terrace-CO singleton frequency that is about 2 cm-1 higher than the edge-CO singleton value.…”

Section: Mixed Isotope Experiments On Saturated Co Adlayersmentioning

confidence: 99%

“…Of value for assessing gross adlayer structural features, is knowledge of the relative intensity of the 12CO and 13 CO spectral features for particular 12 CO percent compositions. These intensity data provide a qualitative measure of the strength of the intermolecular coupling interactions, which is a function of the overall density of the adlayer [24][25][26]28,[31][32][33]38].…”

Section: Saturation Coverage Experimentsmentioning

confidence: 99%

“…[24][25][26]), and it was recently "extended to probe structural aspects of CO adlayers at Pt(l 11) electrodes [27]. Isotopic mixture experiments provide a measure of the extent of adsorbate-adsorbate intermolecular coupling, which is related to gross structural features of the adlayer [24][25][26][27][28][29][30][31][32][33][34]. In the Pt(335)/CO isotopic mixture experiments reported here, two approaches were used to derive adlayer structural information.…”

Section: Introductionmentioning

confidence: 99%

“…The second approach involved using established procedures for determining the dynamical dipole-dipole coupling parameter (Avd) and the static dipole (or chemical) shift parameter (AVs) from the 12 CO and 1 3 CO vibrational mode frequencies measured over a wide range of CO surface coverages and 12 CO/1 3 CO fractions [24][25][26][27][28][29][30][31][32][33][34]. Dipole coupling parameters…”

Section: Introductionmentioning

confidence: 99%

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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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Section: Mixed Isotope Experiments On Saturated Co Adlayersmentioning

confidence: 99%