Dynamics of Potential-Dependent Transformations in Sulfur Adlayers on Au(111) Electrodes

Vericat, Carolina; Andreasen, G.; Vela, M. E.; Salvarezza, Roberto Carlos

doi:10.1021/jp9927451

Cited by 73 publications

(154 citation statements)

References 20 publications

(37 reference statements)

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“…5c is 47 • . The brightness difference between the two S atoms can be due to the different adsorption sites, which has been reported previously [18][19][20][21]. The bright spot in STM image corresponds to the S atom in fcc position and the dark one in hcp position.…”

Section: Adlayer Structure Of Htlsupporting

confidence: 74%

Adlayer structures of dl-homocysteine and l-homocysteine thiolactone on Au(1 1 1) surface: an in situ STM study

Zhang

Wang

et al. 2004

Electrochimica Acta

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The adsorption of dl-homocysteine (Hcy) and l-homocysteine thiolactone (HTL) on Au(1 1 1) electrode was investigated in 0.1 M HClO 4 by cyclic voltammetry and in situ scanning tunneling microscopy (STM). Hcy and HTL molecules formed highly ordered adlayers on Au (1 1 1) surface. High-resolution STM images revealed the orientation and packing arrangement in the ordered adlayers. Hcy molecules formed (2 √ 3 × 3 √ 3)R30 • adlayer structure and H-bonds between carboxyl groups were assumed to be responsible for the origin of tail-to-tail or head-to-head molecular arrangement, while HTL molecules formed (4 × 6) adlayer structure, and two different orientations and appearances in the ordered adlayer were found. Structural models were proposed for the two adlayers.

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Section: Adlayer Structure Of Htlsupporting

confidence: 74%

Adlayer structures of dl-homocysteine and l-homocysteine thiolactone on Au(1 1 1) surface: an in situ STM study

Zhang

Wang

et al. 2004

Electrochimica Acta

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“…15 This so-called electrocompression was also found for the I adlayers on Au͑111͒ [16][17][18][19] and Ag͑111͒. 20 It was also reported that the adlayer structures of S on Au͑111͒ 21, 22 and Ag͑111͒ 23 were dependent on the electrode potential in solution. On Au͑111͒, a () ϫ ))R30°s tructure of S adlayer was observed at negative potentials by in situ STM, 21,22,24 whereas at positive potentials, S clusters like S 8 rings were found with an increase in coverage.…”

mentioning

confidence: 63%

“…When the electrode potential was scanned in the positive direction, triangle clusters made of three S atoms were arranged so as to form a wellordered (ͱ7 ϫ ͱ7)R19.1°structure on Ag͑111͒. 23 As described above, S atoms on Au͑111͒ 21, 22 and Ag͑111͒ 23 in aqueous solutions presented various structures depending on the electrode potential. However, to our knowledge, there has been no in situ STM study performed in solution for the adlayer structure of S on Cu͑111͒.…”

mentioning

confidence: 99%

Structure of Sulfur Adlayer on Cu(111) Electrode in Alkaline Solution

Sugimasa

Inukai

Itaya

2003

J. Electrochem. Soc.

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The structure of sulfur adlayer and the formation process of Cu 2 S layer on Cu͑111͒ were investigated using in situ scanning tunneling microscopy ͑STM͒ in alkaline solution. In situ STM revealed two different structures of the sulfur adlayer, () ϫ ))R30°and (19 ϫ 19), in the double-layer potential region. The () ϫ ))R30°structure observed at negative potentials was transformed into (19 ϫ 19) upon sweeping the potential in the positive direction. The (19 ϫ 19) structure consisted of well-ordered triangular domains separated by boundaries running along the ͗110͘ direction. In each triangular domain of (19 ϫ 19), sulfur atoms were found to form a () ϫ ))R30°structure. Characteristic hexagonal rings consisting of six sulfur atoms were observed at intersections of the domain boundaries of (19 ϫ 19). At anodic potentials, layers of Cu 2 S were epitaxially formed on Cu͑111͒, on which a (ͱ7 ϫ ͱ7)R19.1°structure was observed.Sulfur atoms are known to be strongly adsorbed on metal surfaces and to play important roles in catalysis and many electrochemical reactions such as corrosion. Adlayer structures of S on ͑111͒ surfaces of Pt, 1 Rh, 2 Ni, 3 Pd, 4,5 and Cu 6-12 have been extensively studied in ultrahigh vacuum ͑UHV͒ environment. These studies revealed that the S adlayer forms various ordered structures on ͑111͒ metal surfaces depending on the coverage. Among various metal surfaces, the adsorption of S on Cu͑111͒ has been most intensively studied since S atoms act as a strong poison to Cu-based catalysis, such as the water-gas shift reaction. 9,10 Moreover, the reaction between Cu and S results in the formation of copper sulfide, 6-12 which is a compound semiconductor used in optical devices such as solar cells. 13,14 Adlayer structures of S on Cu͑111͒ surface have been investigated mainly by using scanning tunneling microscopy ͑STM͒ and low-energy electron diffraction ͑LEED͒ under UHV. At a very low S coverage at a low temperature, an STM image was obtained that could be described as (ͱ43 ϫ ͱ43)R Ϯ 7.5°. 12 At a coverage of one-third, it was found by using LEED that S formed a simple () ϫ ))R30°structure. 6 STM studies revealed that when the S coverage was increased, the adlayer structure was changed into ( Ϫ1 4 4 1 ). 7-9 At the saturation coverage, a (ͱ7 ϫ ͱ7)R19.1°structurewas observed by LEED 6,10 as well as STM. 7-9 The ( Ϫ1 4 4 1 ) and the (ͱ7 ϫ ͱ7)R19.1°adlayers were also studied using other techniques, such as surface X-ray diffraction 11 and Auger electron spectroscopy. 10 These studies indicated that the ( Ϫ1 4 4 1 ) and(ͱ7 ϫ ͱ7)R19.1°structures were not simply attributable to the formation of adlayers of S on Cu͑111͒, and that the formation of copper sulfide compounds from a chemical reaction between Cu and S atoms must also be taken into account. According to the previous studies in UHV, the adlayer structure of S on Cu͑111͒ seems to be strongly affected by its coverage. In solution, adlayer structures of specifically adsorbed anions have long been investigated, and several potential-dependent structures ha...

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“…The presence of different in plane orientations could be connected with a possible reconstruction of first S overlayer different from the ( √ 7 × √ 7)R19.1 • structure. On the similar S-Au(1 1 1) system, the S layer presents different coexisting phases (( √ 3 × √ 3)R30 • , trimers and ottomers) which evolve dynamically from one phase to another with time at constant potential [43]. The dynamics strongly depends on the applied potentials.…”

Section: Analysis Of Cds Layers Deposited By Ecalementioning

confidence: 99%

In situ X-ray analysis under controlled potential conditions: An innovative setup and its application to the investigation of ultrathin films electrodeposited on Ag(111)

Foresti

Pozzi

Innocenti

et al. 2006

Electrochimica Acta

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Dynamics of Potential-Dependent Transformations in Sulfur Adlayers on Au(111) Electrodes

Cited by 73 publications

References 20 publications

Adlayer structures of dl-homocysteine and l-homocysteine thiolactone on Au(1 1 1) surface: an in situ STM study

Adlayer structures of dl-homocysteine and l-homocysteine thiolactone on Au(1 1 1) surface: an in situ STM study

Structure of Sulfur Adlayer on Cu(111) Electrode in Alkaline Solution

In situ X-ray analysis under controlled potential conditions: An innovative setup and its application to the investigation of ultrathin films electrodeposited on Ag(111)

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