An in situ STM study of sulphate adsorption on copper(111) in acidic aqueous electrolytes

Li, Wu-Hu; Nichols, Richard J.

doi:10.1016/s0022-0728(98)00205-8

Cited by 73 publications

(27 citation statements)

References 27 publications

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“…The examples in the literature are numerous. For instance, the adsorption of sulfate on (111) surfaces is similar for Pt, Rh, Au, Ir, Pd, Ir, or Cu. − On all these surfaces, an identical rotated √3 × √7 surface structure is observed for the adlayer of sulfate. Thus, it seems reasonable to assume that the here identified mechanism for citrate should also operate at least on pure fcc metals.…”

Section: Resultsmentioning

confidence: 96%

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Why Citrate Shapes Tetrahedral and Octahedral Colloidal Platinum Nanoparticles in Water

et al. 2018

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The performance of many advanced catalytic systems depends not only on the size and composition but also on the specific shape of the metal nanoparticles (NPs) from which they are assembled. In turn, the shape of colloidal NPs depends on the specific capping agent involved in their synthesis, though the mechanism is still poorly understood. Here, supported by electrochemical experiments, FTIR spectra and DFT calculations, on well-defined surfaces, we show how a specific capping agent determines the shape of colloidal NPs.Solvated citrate can become simultaneously adsorbed on the Pt(111) surface through three dehydrogenated carboxylic groups, each one of them in bidentate configuration. On the other basal planes, citrate is adsorbed through only two of them. For this reason, under the synthesis conditions, citrate is more favorably adsorbed on the Pt(111) than on the other two basal planes of platinum. This adsorption behavior explains why colloidal platinum NPs of tetrahedral and octahedral shape are produced when citrate is used as the capping agent in water. The mechanism for citrate would also operate determining the shape of other pure fcc metals and can inspire the engineering of future capping agents.

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Section: Resultsmentioning

confidence: 96%

“…The examples in the literature are numerous. For instance, the adsorption of sulfate on (111) surfaces is similar for Pt, Rh, Au, Ir, Pd, Ir or Cu [62][63][64][65][66][67][68] . On all these surfaces, an identical rotated √3×√7 surface structure is observed for the adlayer of sulfate.…”

Section: Citrate Adsorption On Platinum From Dft Calculationsmentioning

confidence: 99%

Why Citrate Shapes Tetrahedral and Octahedral Colloidal Platinum Nanoparticles in Water

et al. 2018

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“…All these adlayers are based on a 2 1 1 1 2 unit cell. Note, however, that the additional long range modulation of this structure (darker regions) is only observed on copper [13,22]. By means of bias potential dependent (i.e.…”

Section: Methodsmentioning

confidence: 94%

In-situ Characterization of Metal/Electrolyte Interfaces: Sulfate Adsorption on Cu(111)

Arenz

Broekmann

Lennartz

et al. 2001

phys. stat. sol. (a)

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As a prototypical example of a metal-electrolyte interface the adsorption of sulfate on well defined Cu(111) single crystal electrodes from a 5 mM H 2 SO 4 solution has been studied by means of in-situ electrochemical scanning tunneling microscopy (EC-STM) and infrared reflection absorption spectroscopy (IRAS). The EC-STM images show the formation of the well-known Moiré -like structure upon adsorption of sulfate on the Cu(111) surface. While IR frequency data fail to provide information about the anion adsorption site, high-resolution STM images taken under specific tunneling conditions also clearly reveal the C 2v symmetry and the twofold bridging coordination of the sulfate adsorption complex. Analysis of the IR intensities, however, does show that the sulfate adsorption starts at a potential noticeably lower (less anodic) than the potential of first Moiré formation. In this potential region the adsorbed sulfate is very mobile on the surface and difficult to image by STM. Adsorption rate and sulfate coverage are strongly dependent on the electrode potential. The slow adsorption process leading to a well ordered Moiré structure is compared to a fast adsorption process by applying potential steps. Under the latter conditions no or only barely ordered sulfate adlayers are observed with STM. As shown by the IR measurements, however, the saturation coverage is hardly affected by the adsorption rate.

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“…(2) What are the detailed hydrogen-bonding networks that comprise the two-dimensional crystalline adstructure? Importantly, such observations and open questions also exist for other M(111)/H2SO4 solution interfaces (M = Pt, Rh, Cu, Ir, and Pd), [18][19][20][21][22] where the (Ö3´Ö7) adstructures prevail as revealed by EC-STM, but the atomistic structures of these interfaces are also ambiguous. 13,[23][24][25] The difficulties in unambiguously determining the adstructure of the Au(111)(Ö3´Ö7)-adsorbate in previous studies are threefold: (1) The spatial resolution of the EC-STM twenty years ago is not sufficiently high to resolve the atomistic details of adsorbates as sulfate or bisulfate anions, water molecule or hydronium cation; (2) The vibrational frequencies of the EC-IR spectra reported in the literature are higher than 900 cm −1 feature only one or two vibrational modes associated with the sulfate or bisulfate species, while vibrational modes with frequencies below 500 cm −1 , associated with the adsorbate-surface interactions, are missing;…”

Section: Introductionmentioning

confidence: 99%

Revisiting the Atomistic Structures at the Interface of Au(111) Electrode–Sulfuric Acid Solution

et al. 2020

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Knowledge of atomistic structures at solid/liquid interfaces is essential to elucidate interfacial processes in chemistry, physics, and materials sciences. The (Ö3´Ö7) structure associated with a pair of sharp reversible current spikes in the cyclic voltammogram on a Au(111) electrode in sulfuric acid solution, represents one of the most classical structures at electrode/electrolyte interfaces. Although more than ten adsorption configurations have been proposed by more than ten groups in the past four decades, the atomistic structure remains ambiguous and is consequently an open problem in electrochemistry and surface science. Herein, by combining high-resolution electrochemical scanning tuning microscopy, electrochemical infrared and Raman spectroscopies, and in particular, the newly developed quantitative computational method for electrochemical infrared and Raman spectra, we unambiguously reveal that the adstructure is Au(111)(Ö3´Ö7)-(SO4•••w2) with a sulfate anion (SO4*) and two structured-water molecules (w2*) in a unit cell, and the crisscrossed [w•••SO4•••w]n and [w•••w•••]n hydrogen-bonding network comprises the symmetric adstructure. We further elucidate that the electrostatic potential energy dictates the proton affinity of sulfate anions, leading to the potential-tuned structural transformations. Our work enlightens the structural details of the inner Helmholtz plane and thus advances our fundamental understanding of the processes at electrochemical interfaces.

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An in situ STM study of sulphate adsorption on copper(111) in acidic aqueous electrolytes

Cited by 73 publications

References 27 publications

Why Citrate Shapes Tetrahedral and Octahedral Colloidal Platinum Nanoparticles in Water

Why Citrate Shapes Tetrahedral and Octahedral Colloidal Platinum Nanoparticles in Water

In-situ Characterization of Metal/Electrolyte Interfaces: Sulfate Adsorption on Cu(111)

Revisiting the Atomistic Structures at the Interface of Au(111) Electrode–Sulfuric Acid Solution

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