Surface coordination chemistry of well-defined platinum electrodes: surface polyprotic acidity of platinum(111)(2 .sqroot. 3 .times. 2 .sqroot. 3)R30.degree.-hydrogen isocyanide

Schardt, Bruce C.; Stickney, John L.; Stern, Donald A.; Frank, Douglas G.; Katekaru, James Y.; Rosasco, Stephen D.; Salaita, Ghaleb N.; Soriaga, Manuel P.; Hubbard, Arthur T.

doi:10.1021/ic00204a001

Cited by 38 publications

(17 citation statements)

References 1 publication

Supporting

Mentioning

Contrasting

Order By: Relevance

“…If these sites remain electronically unaltered, hydrogen evolution would be expected to coincide on both Pt(111) and cyanide-modified Pt(111) electrodes.The shift in the onset of hydrogen adsorption can be explained by the formation in the H upd region of adsorbed hydrogen isocyanide, CNH ad , instead of H ad directly bonded to the Pt atoms. This idea had been already proposed by Schardt et al[27], who suggested that the CNH ad adlayer behaves as a polyprotic acid. The formation of…”

mentioning

confidence: 73%

Cyanide-modified Pt(111): Structure, stability and hydrogen adsorption

Escudero-Escribano

Soldano

Quaino

et al. 2012

Electrochimica Acta

View full text Add to dashboard Cite

Cyanide-modified Pt(111) surfaces have been recently used to study atomic-ensemble effects in electrocatalysis. These studies have been based on the assumption that cyanide acts as a third body, blocking some surface sites but leaving the electronic properties of the surrounding ones unaltered, although this is in apparent contradiction with the observation of a positive shift of 0.2 V in the onset of hydrogen adsorption on cyanide-modified Pt(111) electrodes, as compared with clean Pt(111). We have performed theoretical calculations in order to provide support to this assumption and explain the positive shift in the onset of hydrogen adsorption, which is shown to be due to the formation of CNH ad .

show abstract

mentioning

confidence: 73%

Cyanide-modified Pt(111): Structure, stability and hydrogen adsorption

Escudero-Escribano

Soldano

Quaino

et al. 2012

Electrochimica Acta

View full text Add to dashboard Cite

show abstract

“…[32] We have recently suggested that the increase in DG 0 of H upd is due to the formation of (CN ad ) x -H clusters. [32,33] Formation of adsorbed isocyanide (CNH ads ) was also argued by Schardt et al [34] (who suggested that the whole surface of the cyanidemodified Pt(111) electrode behaves as a polyprotic acid) in order to explain the effect of pH on the amount of Cs + retained on the surface of a cyanide-modified Pt(111) electrode after immersion in a 0.1 mm CsCl solution. The formation of (CN ad ) x -H clusters (where x must decrease with decreasing potential within the H upd region) can also explain the change in the Stark tuning rate of the CN stretching frequency of a cyanide-modified Pt(111) electrode occurring at potentials more negative than 0.6 V versus RHE [26d, 27e] (coinciding with the onset of H upd formation) and the incomplete blocking of hydrogen adsorption after adsorption of CO to saturation on a cyanide-modified Pt(111) electrode.…”

Section: The Cyanide-modified Pt(111) Electrode: Structure and Propermentioning

confidence: 86%

Atomic Ensemble Effects in Electrocatalysis: The Site‐Knockout Strategy

Cuesta

2011

ChemPhysChem

View full text Add to dashboard Cite

During an electrocatalytic reaction bonds are broken and formed, and this requires that the reactants, the intermediates formed at the elementary reaction steps, and the products interact with a given number of surface atoms of the catalyst. Modifying the number of groups with an adequate number of surface atoms in a suitable geometric arrangement for a determined reaction step to proceed may affect the activity and/or selectivity of the catalyst. Although separating purely geometric atomic ensemble effects from electronic effects is not straightforward, the insights extracted from a detailed investigation of atomic ensemble effects can have a profound impact in the determination of electrocatalytic reaction mechanisms and in the design of more active and more selective electrocatalysts. This Minireview illustrates, using cyanide‐modified Pt(111) electrodes as an archetype, how eliminating only one kind of site from the surface (the site‐knockout strategy) by means of a regular array of inert adsorbates can be used to successfully study atomic ensemble effects in electrocatalysis. The possible consequences for the design of more efficient and more selective electrocatalysts are also commented on.

show abstract

“…Measurement of Absolute Surface Concentrations and Adsorbed-Molecule Orientations [19,20] Such measurement takes advantage of the fact that the redox (quinone-diphenol) chemistry of the unadsorbed H 2 Q (or BQ) is vastly different from that of the irreversibly adsorbed species [4,5,9,21]. Hence, the difference between the H 2 Q (or BQ) concentration in the bulk solution and inside the thin-layer cell (immediately after chemisorption) is a measure of the amount of organic that is coordinated to the surface.…”

Section: Thin-layer Electroanalysis In Surface Electrochemistrymentioning

confidence: 99%

“…In this regard, we have examined the surface-coordination properties of noble-metal electrodes when exposed to aqueous solutions that typical preselected surface-active functional groups; such groups range from simple halides [3] to more complex aromatic molecules [4,5]. Indeed, at least in terms of modes of binding and strengths of chemisorption, we found a distinct correlation between the homogeneous and the interfacial systems [5,6].…”

Section: Introductionmentioning

confidence: 99%

The Use of Thin‐Layer Electroanalysis in the Study of the Chemisorption and Anodic Oxidation of Aromatic Molecules at Smooth Polycrystalline Palladium

2005

View full text Add to dashboard Cite

Thin-layer electroanalytical chemistry has been used in the study of the chemisorption and anodic oxidation of hydroquinone and benzoquinone at smooth polycrystalline palladium electrode surfaces in aqueous sulfuric acid solutions. The results were reminiscent of those obtained previously on smooth polycrystalline platinum: i) At low aqueous-solution concentrations, the diphenol is oxidatively chemisorbed to form surface-coordinated benzoquinone oriented parallel to the surface. ii) At higher concentrations, the oxidative chemisorption occurs via CÀH activation to yield an edge-oriented diphenolic species. iii) Chemisorption from benzoquinone solutions leads to species identical to those from hydroquinone solutions. iv) The extent of anodic oxidation of the chemisorbed organic depends upon the initial adsorbed-molecule orientation: the flat-adsorbed species are oxidized completely to carbon dioxide, whereas oxidation of the edge-chemisorbed species yields other (unidentified) products that are chemisorbed upon regeneration of the oxide-free surface.

show abstract

Surface coordination chemistry of well-defined platinum electrodes: surface polyprotic acidity of platinum(111)(2 .sqroot. 3 .times. 2 .sqroot. 3)R30.degree.-hydrogen isocyanide

Cited by 38 publications

References 1 publication

Cyanide-modified Pt(111): Structure, stability and hydrogen adsorption

Cyanide-modified Pt(111): Structure, stability and hydrogen adsorption

Atomic Ensemble Effects in Electrocatalysis: The Site‐Knockout Strategy

The Use of Thin‐Layer Electroanalysis in the Study of the Chemisorption and Anodic Oxidation of Aromatic Molecules at Smooth Polycrystalline Palladium

Contact Info

Product

Resources

About