In-situ STM investigation of specific anion adsorption on Cu(111)

Broekmann, Peter; Wilms, Michael; Kruft, M.; Stuhlmann, Christopher; Wandelt, K.

doi:10.1016/s0022-0728(99)00048-0

Cited by 154 publications

(178 citation statements)

References 41 publications

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“…Both preparation methods yield clean and well defined surfaces for STM investigations. In order to avoid contaminations, the Cu(1 1 1) crystal was not exposed to a halide containing electrolyte which can be used to increase the mobility of step edges [12], therefore its average terrace width was significantly smaller than that of the flame annealed Au (1 1 1 buffer solution (pH = 6.8), as used in the present study, is dihydrogenphosphate, in the following discussion the term phosphate is used for denoting any adsorbed anionic phosphate species, as, like for the discussion of (bi)sulfate adsorption, the exact chemical nature of the adsorbed phosphate species remains unclear.…”

Section: Methodsmentioning

confidence: 99%

In-situ STM study of phosphate adsorption on Cu(111), Au(111) and Cu/Au(111) electrodes

Schlaup

Horch

2013

Surface Science

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The interaction of Cu(1 1 1), Au(1 1 1) and Cu-covered Au(1 1 1) electrodes with a neutral phosphate buffer solution has been studied by means of cyclic voltammetry (CV) and in situ electrochemical scanning tunneling microscopy (EC-STM). Under low potential conditions, both the Cu (1 1 1) and the Au(1 1 1) surface appear apparently adsorbate free, indicated by the presence of a (4 × 4) structure and the herringbone surface reconstruction, respectively. Upon potential increase, phosphate anions adsorb on both surfaces and for Cu(1 1 1) the formation of a (• structure is found, whereas on Au(1 1 1) a "( √ 3× √ 7)" structure is formed. For a Cu-submonolayer on Au(1 1 1), coadsorption of phosphate anions leads to the formation of a (2 × 2) vacancy structure within an assumed pseudomorphic structure of the Cu-submonolayer with the phosphate anions occupying the vacancies. When desorbing the phosphate anions at low potentials, the Cu-submonolayer first becomes mobile and eventually undergoes an irreversible transition to a coalescent nonpseudomorphic structure.

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Section: Methodsmentioning

confidence: 99%

In-situ STM study of phosphate adsorption on Cu(111), Au(111) and Cu/Au(111) electrodes

Schlaup

Horch

2013

Surface Science

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“…[10][11][12] There have been various studies dealing with the overall morphology of a surface with steps and how this morphology is affected by adsorbates. [13][14][15][16][17] Here we report on the restructuring of a stepped platinum surface in the presence of adsorbed ammonia. We focus, however, on a single step and on the details of the meandering of such step.…”

Section: Frozen Thermal Fluctuations In Adsorbate-induced Step Restrumentioning

confidence: 96%

Frozen thermal fluctuations in adsorbate-induced step restructuring

et al. 2010

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“…It has been proven that the chloride desorption/adsorption process through a condensed viologen film is reversible between À320 mV and À350 mV. [15] Therefore, the appearance of the peak P 3 /P 3 ' is regarded as a signal of such a reversible process. After desorption of the chloride adlayer from the metallic copper substrate, the active radical cationic DHVC + phase can still organize itself to remain adsorbed on the bare Cu electrode surface accompanied by the appearance of P 4 /P 4 ' peak in the CVs.…”

Section: Electrochemical Behaviour Of Heptyl Viologen On a Cu(100) Elmentioning

confidence: 99%

“…It is well-known that the chloride ions adsorb preferentially and form a well-ordered c(22)-Cl phase, and that they induce a preferential step alignment parallel to the close-packed chloride rows, which are rotated by 458 with respect to the main symmetry axis of the underlying copper substrate. [12][13][14][15] Figure 2 a shows a representative STM image of a highly ordered "dot-array" phase in the presence of DHV 2 + dications. As shown in Figure 2 Figure 2 b).…”

Section: Electrochemical Behaviour Of Heptyl Viologen On a Cu(100) Elmentioning

confidence: 99%

“…[9][10][11][12] Halide ions (Cl À , Br À , I À ) have been found to form condensed and highly ordered adsorbate layers on some single-crystal electrode surfaces, which makes these halidemodified electrodes interesting electronic templates for the adsorption of positively charged organic molecules. [9,10,[12][13][14][15] Such a model has been applied in the adsorption of viologen species on metal electrodes. [16][17][18][19][20] Viologens (N,N'-disubstituted-4,4'-bipyridinium molecules) are one important class of redox-active compounds which have attracted much attention as electron-transfer mediators in photochemical devices for solar energy conversion and as materials for electrochromic displays.…”

Section: Introductionmentioning

confidence: 99%

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Redox Activity and Structural Transition of Heptyl Viologen Adlayers on Cu(100)

Jiang¹,

Sak²,

Gentz³

et al. 2010

ChemPhysChem

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The redox behaviour and potential-dependent adsorption structure of heptyl viologen (1,1'-diheptyl-4,4'-bipyridinium dichloride, DHV(2+)) on a Cu(100) electrode was investigated in a chloride-containing electrolyte solution by cyclic voltammetry (CV) and in situ electrochemical scanning tunneling microscopy (EC-STM). The dicationic DHV molecules generate a few pairs of current waves in CV measurements which are ascribed to two typical one-electron transfer steps. STM images obtained in a KCl-containing electrolyte solution disclose a well-ordered c(2x2) chloride adlayer on a Cu(100) electrode surface. After injecting DHV(2+) molecules into the KCl electrolyte solution, a highly ordered 2D "dot-array" structure in STM images emerges on the c(2x2)-Cl modified Cu(100) electrode surface. DHV(2+) molecules spontaneously arrange themselves with their molecular planes facing the electrode surface and their long molecular axis parallel to the step edge. Such adsorption structure can be described by mirror domains and rotational domains which stably exist between 200 mV and -100 mV. One-electron reduction of the dications DHV(2+) around -150 mV causes a phase transition from a 'dot-array' assembly to a stripe pattern formed by DHV(*+) radical monocations in STM images which has a bilayer structure. With a further decrease of the applied electrode potential, the structure of the DHV(*+) adlayer undergoes a change from a loose stripe phase to a more compact stripe phase, a subsequent decay of the compact structure, and finally the formation of a new dimer phase. A further electron transfer reaction at -400 mV causes the formation of an amorphous phase on the chloride free electrode surface. In a reverse anodic sweep, the reproduction of the ordered DHV(*+) stacking phase occurs again on top of the chloride lattice.

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In-situ STM investigation of specific anion adsorption on Cu(111)

Cited by 154 publications

References 41 publications

In-situ STM study of phosphate adsorption on Cu(111), Au(111) and Cu/Au(111) electrodes

In-situ STM study of phosphate adsorption on Cu(111), Au(111) and Cu/Au(111) electrodes

Frozen thermal fluctuations in adsorbate-induced step restructuring

Redox Activity and Structural Transition of Heptyl Viologen Adlayers on Cu(100)

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