In situ Video-STM studies of sulfate dynamics on Au(1 1 1)

Suto, Koji; Magnussen, Olaf M.

doi:10.1016/j.jelechem.2010.02.016

Cited by 23 publications

(24 citation statements)

References 24 publications

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“…A typical CV of the Au(111) electrode in 0.1 M H2SO4 was recorded from 0.05 to 1.2 V vs. SHE away from the characteristic voltages regarding hydrogen or oxygen evolution processes ( Figure 1A). The CV shows a pair of sharp spikes at approximately 1.06 V (red lines), which is consistent with the results from the literature, 15,[41][42] and indicates the high quality of the Au(111) single-crystal electrode in this work.…”

Section: Resultssupporting

confidence: 92%

“…The STM image shows many detailed features that were not resolved before. [10][11]15,42 In particular, we observed zig-zag chains (dashed yellow line segments along the Ö3 direction) and two lobes (dashed red lines along the direction of a) going through and inside the yellow frame, respectively.…”

Section: Determining the Adstructure From Nine Possible Configurationmentioning

confidence: 79%

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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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Section: Resultssupporting

confidence: 92%

Section: Determining the Adstructure From Nine Possible Configurationmentioning

confidence: 79%

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

et al. 2020

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“…28,29 Furthermore, video STM allowed the observation of short-lived local configurations of adsorbed sulfate on Au(111), providing insight into the intermolecular interactions. 30 In the video-STM studies presented here, similar data are reported for methyl thiolates in the potential regime, where the Cu(100) surface is covered with an ordered c(2 × 2) chloride adlayer. 31,32 We first describe studies of the surface diffusion and the pairwise adsorbate interactions in the range of low thiolate coverages, which form a basis for the subsequent discussion of larger molecular structures.…”

Section: Introductionsupporting

confidence: 79%

In Situ Video-STM Studies of Methyl Thiolate Surface Dynamics and Self-Assembly on Cu(100) Electrodes

2012

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The atomic-scale surface dynamic behavior of adsorbed methyl thiolate on Cu(100) electrodes, prepared via the dissociative adsorption of dimethyl disulfide, was studied in 0.01 M HCl solution over a wide regime of coverages. Using video-rate in situ STM, we directly observed the motion of the adsorbates within the c(2 × 2) lattice of the chloride coadsorbates with high spatial and temporal resolution, revealing complex mutual interactions of the organic adsorbates as well as pronounced interactions with Cu adatoms, which significantly affect the thiolate self-assembly. Quantitative measurements of the tracer diffusion of isolated thiolates reveal a 35 meV lower diffusion barrier as compared to that of sulfide adsorbates with a linear potential dependence of 0.5 eV/V. The effective intermolecular interactions between the thiolates resemble those between adsorbed sulfide and are repulsive at the nearest-neighbor distance of a(0) within the c(2 × 2) lattice, attractive at the next-nearest-neighbor distance of √2a(0) and again repulsive at a distance of 2a(0). Thiolates at these small spacings are found to exhibit characteristic collective properties, which are significant for the self-assembly of these species: First, their mobility is greatly enhanced relative to that of isolated thiolates. Second, Cu adatoms can be transiently trapped in between the two thiolates of a metastable dimer with an intermolecular spacing of √2a(0). With increasing coverage, small, highly mobile molecular clusters and subsequently the formation of ordered adlayer domains with a c(2 × 6) structure are observed. Common structural elements of the clusters and c(2 × 6) domains are stripes of thiolate dimers, which are oriented in the [011] direction, spaced at distances of √2a(0) and of which a large fraction is occupied by Cu adatoms. The c(2 × 6) phase can be rationalized as a close-packed arrangement of these dimer stripes. Because of the self-acceleration of the thiolate mobility, the ordering and reorganization of the ordered c(2 × 6) adlayers occur orders of magnitude faster than the surface diffusion of isolated thiolates, illustrating the importance of collective effects in organic self-organization.

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“…The STM image is strongly associated with the trapping of HSO 4 − or Cl − ions (derived from the counterions of 1 ) by the highly ordered arrays of 4 . In general, bisulfate anions are highly mobile on a Au(111) surface at potentials nearly equal to OCP . It is also well‐known that halide ions strongly adsorb on metal surfaces (so‐called “specific adsorption”) .…”

Section: Methodsmentioning

confidence: 99%

A Supramolecular Approach to the Preparation of Nanographene Adlayers Using Water‐Soluble Molecular Capsules

2018

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Polycyclic aromatic hydrocarbons (PAHs) are excellent building blocks for the creation of two-dimensional (2D) nanosheets.However,large PAHs tend to exhibit poor or no solubility in organic solvents and water.T oo vercome this issue,w ee mployed water-soluble micellar capsules consisting of V-shaped amphiphilic molecules.C haracteristic electrochemical behavior was observed in 0.1m H 2 SO 4 in the presence of the water-soluble capsules containing PAHs,s uch as ovalene,c ircobiphenyl, and dicoronylene.F urthermore, under these conditions,P AHs were released from the capsules, resulting in the formation of a2 Da dlayer of PAHs at the electrochemical interface.F inally,u sing electrochemical scanning tunneling microscopy, we demonstrate that our molecular containers based on water-soluble molecular capsules allowthe facile preparation of 2D PAHa dlayers in addition to structurally controlling nanostructure formation on Au surfaces.Carbon materials,s uch as graphene,h ave been extensively studied for their application in electronic devices, [1][2][3] photodetectors, [4][5][6] capacitors, [7] electrocatalysis, [8][9][10] and sensors. [11] Similarly,p olycyclic aromatic hydrocarbons (PAHs) with planar structures exhibit excellent donor abilities owing to their p-conjugated structures.A ss uch, PA Hs are promising materials for use as two-dimensional (2D) nanoarchitectures, such as "nanographene", which should create novel functionalities for electronic devices,i ncluding electrochromic devices [1,12] and quantum dots. [13] Fore xample,f unctionalized graphene quantum dots that allow the control of band gaps indicate the structural dependence of photocatalysts in water splitting and carbon dioxide reduction under visible-light irradiation. [13] Indeed, to date,anumber of attractive PA Hs have been synthesized by the Müllen group. [1, 12,14] Thedesign and synthesis of structurally defined PA Hs are essential for the creation of functional graphenes based on elemental doping and periodical defects (or vacancies) as the building blocks.However,large PA Hs without peripheral substituents are insoluble in both water and organic solvents.T he formation of adlayers on electrode surfaces is challenging because PA Hs without peripheral substituents are used as 2D molecular templates, [15] have applications in conductance enhancement between nanographene and Au junctions, [16] and are used in organic field-effect transistors (OFETs). [17] In contrast, the V-shaped amphiphilic molecule 1 (Scheme 1) forms micellar capsules (1) n in water and solubilizes various water-insoluble compounds.I np articular, p-conjugated planar molecules,s uch as metalloporphyrins,p hthalocyanines,p entacenes,a nd coronenes,h ave been applied for this purpose. [18,19] We report herein water-soluble molecular capsules consisting of V-shaped amphiphilic molecules for the uptake of large PA Hs (i.e., ovalene,c ircobiphenyl, and dicoronylene; Scheme 1). In this study,w ea lso examined the electrochemical behavior of the PA H-containing molecular capsules an...

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In situ Video-STM studies of sulfate dynamics on Au(1 1 1)

Cited by 23 publications

References 24 publications

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

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

In Situ Video-STM Studies of Methyl Thiolate Surface Dynamics and Self-Assembly on Cu(100) Electrodes

A Supramolecular Approach to the Preparation of Nanographene Adlayers Using Water‐Soluble Molecular Capsules

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