Combining Vibrational Spectroscopy and Density Functional Theory for Probing Electrosorption and Electrocatalytic Reactions

Koper, Marc T. M.

doi:10.1002/9780470929421.ch7

Cited by 3 publications

(2 citation statements)

References 49 publications

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“…[48][49][50] SERS results confirm the involvement of formate as an intermediate during the electrooxidation process on Au. 26,37 When both results are correlated to each other, the study leads to edifying results. The unobservable intensity of formate in the anodic scan is due to the negligible catalytic activity of the bare Au surface toward formic acid oxidation at low potentials and the removal of formic acid by surface gold oxide at high potentials above 1.0 V. As the potential is scanned negatively, surface oxide is removed which leaves vacant sites for the adsorption of formate on the bare Au surface.…”

Section: Discussionmentioning

confidence: 99%

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In situ surface-enhanced Raman spectroscopic study of formic acid electrooxidation on spontaneously deposited platinum on gold

Muralidharan

McIntosh

2013

Phys. Chem. Chem. Phys.

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Present formic acid fuel cell efficiency is limited by low kinetics at the anode, indicating the need for effective catalysts to improve the formic acid oxidation. As a prerequisite, the nature of adsorbed species and specifically the reaction intermediates formed in this process needs to be examined. This work focuses on the electrooxidation of formic acid and the nature of the intermediates at a platinum-modified gold surface prepared through spontaneous deposition using a combination of electrochemistry and in situ surface enhanced Raman spectroscopy (SERS). This Pt-modified gold electrode surface assists in oxidizing formic acid at potentials as low as 0.0 V vs. Ag/AgCl which is 0.15 V more negative than a bare Pt surface. The oxidation current obtained on the Pt-modified gold electrode is 72 times higher than on a bare Au surface and 5 times higher than on a bare Pt surface at the same potential. In situ SERS has revealed the involvement of formate at a low frequency as the primary intermediate in this electrooxidation process. While previous studies mainly focused on the formate mode at ca. 1322 cm(-1), it is the first time that a formate peak at ca. 300 cm(-1) was observed on a Pt or Pt-associated surface. A unique relationship has been observed between the formic acid oxidation currents and the SERS intensity of this formate adsorbate. Furthermore, the characteristic Stark effect of the formate proves the strong interaction between the adsorbate and the catalyst. Both electrochemical and spectroscopic results suggest that the formic acid electrooxidation takes place by the dehydrogenation pathway involving a low frequency formate intermediate on the Pt-modified gold electrode catalyst.

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Section: Discussionmentioning

confidence: 99%

“…26 The positive Stark effect value shows that the adsorbate is anionic. 26,37 3.3.3 SERS on a Pt-modified gold electrode surface in blank solution. Fig.…”

Section: In Situ Surface Enhanced Raman Spectroscopy (Sers) Studiesmentioning

confidence: 99%

In situ surface-enhanced Raman spectroscopic study of formic acid electrooxidation on spontaneously deposited platinum on gold

Muralidharan

McIntosh

2013

Phys. Chem. Chem. Phys.

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Position of Cu Atoms at the Pt(111) Electrode Surfaces Controls Electrosorption of (H)SO₄⁽²⁾⁻ from H₂SO₄ Electrolytes

2013

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Selective positioning of monolayer amounts of foreign atoms at the surface and subsurface regions of metal electrodes is a promising way to fine‐tune the properties of the electrode/electrolyte interface. The latter is critical as it largely governs the adsorption of electrolyte components and reaction intermediates and, therefore, controls many key electrocatalytic processes. Using model Pt(111) single‐crystal electrodes, we demonstrate how the relative position of Cu atoms at the surface drastically changes the adsorption energies for (bi)sulfate anions. Our measurements involve pseudomorphic overlayers of Cu on Pt(111) as well as Cu–Pt(111) surface and sub‐surface alloys, where Cu atoms were located either in the first or in the second atomic layers of Pt, respectively. In the case of Cu–Pt(111) surface alloys, specific adsorption of the anions starts earlier compared to the unmodified Pt(111) surface. In contrast, placing Cu atoms into the second atomic layer weakens the binding between the surface and the anions. Surprisingly, Cu pseudomorphic overlayers do not reveal any specific adsorption of (bi)sulfates (within the region of the overlayer stability). Taking into account that electrified interfaces between Pt(111) electrodes and sulfate‐containing electrolytes often play the role of benchmark systems in fundamental physico‐chemical and, particularly, electrocatalytic studies, our findings demonstrate a promising and relatively easy route of tuning the properties of these interfaces.

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Localized Electrochemical Impedance Spectroscopy: Visualization of Spatial Distributions of the Key Parameters Describing Solid/Liquid Interfaces

et al. 2013

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Acquisition of localized electrochemical impedance spectra as a function of spatial coordinates combined with novel approaches of data analysis brings a key for visualization of two-dimensional distributions of important parameters describing solid/liquid interfaces. They include the capacitance of the electric double layer, the resistance of the interfacial charge transfer, capacitances of adsorption, or other parameters depending on the properties of the system. Additionally, the proposed approach eliminates many common methodological problems of localized electrochemical impedance microscopies related to the frequency dependence of the actual pictures and difficulties with raw data interpretation. Thus, it offers a unique insight into the localized processes at the interface which is not possible to achieve using classical techniques.

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Combining Vibrational Spectroscopy and Density Functional Theory for Probing Electrosorption and Electrocatalytic Reactions

Cited by 3 publications

References 49 publications

In situ surface-enhanced Raman spectroscopic study of formic acid electrooxidation on spontaneously deposited platinum on gold

In situ surface-enhanced Raman spectroscopic study of formic acid electrooxidation on spontaneously deposited platinum on gold

Position of Cu Atoms at the Pt(111) Electrode Surfaces Controls Electrosorption of (H)SO₄⁽²⁾⁻ from H₂SO₄ Electrolytes

Localized Electrochemical Impedance Spectroscopy: Visualization of Spatial Distributions of the Key Parameters Describing Solid/Liquid Interfaces

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Combining Vibrational Spectroscopy and Density Functional Theory for Probing Electrosorption and Electrocatalytic Reactions

Cited by 3 publications

References 49 publications

In situ surface-enhanced Raman spectroscopic study of formic acid electrooxidation on spontaneously deposited platinum on gold

In situ surface-enhanced Raman spectroscopic study of formic acid electrooxidation on spontaneously deposited platinum on gold

Position of Cu Atoms at the Pt(111) Electrode Surfaces Controls Electrosorption of (H)SO4(2)− from H2SO4 Electrolytes

Localized Electrochemical Impedance Spectroscopy: Visualization of Spatial Distributions of the Key Parameters Describing Solid/Liquid Interfaces

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Position of Cu Atoms at the Pt(111) Electrode Surfaces Controls Electrosorption of (H)SO₄⁽²⁾⁻ from H₂SO₄ Electrolytes