Role of double-layer cation on the potential-dependent stretching frequencies and binding geometries of carbon monoxide at platinum-nonaqueous interfaces

Roth, Joseph D.; Weaver, Michael J.

doi:10.1021/la00041a034

Cited by 56 publications

(49 citation statements)

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“…The latter was calculated from the cation's limiting molar conductivity,  (see SI). Similar cation effects on the STR have been found by Roth and Weaver [16] for COad on Pt in non-aqueous media, and have also been recently reported for COad on Cu [15,33]. The values of the STR for all the cations used in this study are provided in , with o the vacuum permittivity and  the dielectric constant of the interfacial region As shown in Fig.…”

Section: Cation Effect On the Potential Dependence Of ̅supporting

confidence: 81%

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How cations determine the interfacial potential profile: Relevance for the CO2 reduction reaction

Hussain

Pérez-Martínez

et al. 2019

Electrochimica Acta

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The strong effect of the electrolyte cation on the activity and selectivity of the CO2 reduction reaction (CO2RR) can only be understood and controlled if the cation's effect on the interfacial potential distribution is known. Using CO (the key intermediate in the CO2RR) adsorbed on Pt as a probe molecule, and combining IR spectroscopy, capacitance measurements and ab initio molecular dynamics, we show that the cation size determines the location of the outer Helmholtz plane, whereby smaller cations increase not just the polarisation but, most importantly, the polarizability of adsorbed CO (COad) and the accumulation of electronic density on the oxygen atom of COad. This strongly affects its adsorption energy, the degree of hydrogen bonding of interfacial water to COad and the degree of polarisation of water molecules in the cation's solvation shell, all of which can deeply affect the subsequent steps of the CO2RR.

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Section: Cation Effect On the Potential Dependence Of ̅supporting

confidence: 81%

“…They have been very well characterised spectroscopically and electrochemically [16][17][18][19][20][21][22][23][24]. CO adsorbs strongly on Pt, remains in the same structure over a wide potential range, and blocks the specific adsorption of ions on the electrode surface.…”

Section: Introductionmentioning

confidence: 99%

How cations determine the interfacial potential profile: Relevance for the CO2 reduction reaction

Hussain

Pérez-Martínez

et al. 2019

Electrochimica Acta

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“…To overcome this limitation, we and other teams have worked in CO saturated nonaqueous (e.g. acetonitrile) oxygen-free solutions 38,39,40 , hence extending the working potential range from 0.8V to about 2.7V. The Weaver group could consequently measure the variation of the Stark slope over a wide potential range as a function of the solvent and the nature of the counter ions 38,39 , explaining the observed values by the varying thickness of the effective double layer.…”

Section: Introductionmentioning

confidence: 99%

Enhanced Stability of a Carbon Monoxide Monolayer Adsorbed on Platinum under Electrochemical Control Probed by Sum-Frequency Generation Spectroscopy

2016

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We establish a new procedure to study the steady state adsorption of carbon monoxide (CO) at the surface of platinum under electrochemical control over a wide potential range in aqueous acidic solution. Using highly concentrated solutions of CO in perchloric acid medium enables the formation of a tightly packed and very stable CO monolayer at the surface of the metal, which allows cyclic voltammetry in the [-1200;+1500mV] potential range (vs Ag/AgCl). We use Sum-Frequency Generation (SFG) spectroscopy to show the unusual stability of the monolayer: going towards negative potentials, hydrogen evolution is first blocked then strongly quenched; towards positive potentials, CO oxidation is prevented as a consequence of its dense packing as a "frozen" monolayer. Diluting CO concentration by a factor of ten is enough to recover most of the usual properties of the CO/Pt(110) interface, still maintaining the high stability of the CO adlayer. Such a protocol can be applied to any problem for which CO poisoning mechanism has to be scrutinized or as a model of very stable electrochemical interfaces for fundamental studies.

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“…CO-terminated Pt surfaces are particularly well characterized, with electrochemical ca-pacitance measurements in a range of solvents including water, acetonitrile and ionic liquids. [17][18][19] The classical double layer model for this system consists of an inner layer with a linear potential drop covering the CO adlayer and extending till the outer Helmholtz plane, assumed to be one radius of unsolvated electrolyte ion beyond the first water layer. 17 Smith and White 12 proposed an alternate model for electroactive films in which the potential drops linearly across a dielectric, and then decays rapidly in the electrolyte.…”

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confidence: 99%

Electrochemical Capacitance of CO-Terminated Pt(111) Dominated by the CO–Solvent Gap

Sundararaman

Figueiredo

Koper

et al. 2017

J. Phys. Chem. Lett.

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The distribution of electric fields within the electrochemical double layer depends on both the electrode and electrolyte in complex ways. These fields strongly influence chemical dynamics in the electrode-electrolyte interface, but cannot be measured directly with sub-molecular resolution. We report experimental capacitance measurements for aqueous interfaces of CO-terminated Pt(111). By comparing these measurements with first-principles density-functional theory (DFT) calculations, we infer microscopic field distributions and decompose contributions to the inverse capacitance from various spatial regions of the interface. We find that the CO is strongly electronically coupled to the Pt, and that most of the interfacial potential difference appears across the gap between the terminating O and water, and not across the CO molecule as previously hypothesized. This ‘gap capacitance' resulting from hydrophobic termination lowers the overall capacitance of the aqueous Pt-CO interface, and makes it less sensitive to electrolyte concentration compared to the bare metal.

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Role of double-layer cation on the potential-dependent stretching frequencies and binding geometries of carbon monoxide at platinum-nonaqueous interfaces

Cited by 56 publications

References 2 publications

How cations determine the interfacial potential profile: Relevance for the CO2 reduction reaction

How cations determine the interfacial potential profile: Relevance for the CO2 reduction reaction

Enhanced Stability of a Carbon Monoxide Monolayer Adsorbed on Platinum under Electrochemical Control Probed by Sum-Frequency Generation Spectroscopy

Electrochemical Capacitance of CO-Terminated Pt(111) Dominated by the CO–Solvent Gap

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