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Titolo:
Atomic structures and dynamics of a Cu(100) electrode in dilute hydrobromic acid: An in situ STM study
Autore:
Broekmann, P; Anastasescu, M; Spaenig, A; Lisowski, W; Wandelt, K;
Indirizzi:
Univ Bonn, Inst Phys & Theoret Chem, D-53115 Bonn, Germany Univ Bonn Bonn Germany D-53115 hys & Theoret Chem, D-53115 Bonn, Germany Polish Acad Sci, Inst Phys Chem, PL-01224 Warsaw, Poland Polish Acad Sci Warsaw Poland PL-01224 hys Chem, PL-01224 Warsaw, Poland
Titolo Testata:
JOURNAL OF ELECTROANALYTICAL CHEMISTRY
fascicolo: 1-2, volume: 500, anno: 2001,
pagine: 241 - 254
Fonte:
ISI
Lingua:
ENG
Soggetto:
SCANNING-TUNNELING-MICROSCOPY; IN-SITU; CHLORIDE ADSORPTION; CU(111) ELECTRODES; BROMIDE ADSORPTION; HCL SOLUTIONS; EX-SITU; DISSOLUTION; SURFACE; IODINE;
Keywords:
Cu(100) electrode; bromide adsorption; in situ STM;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Physical, Chemical & Earth Sciences
Citazioni:
26
Recensione:
Indirizzi per estratti:
Indirizzo: Broekmann, P Univ Bonn, Inst Phys & Theoret Chem, Wegelerstr 12, D-53115 Bonn, Germany Univ Bonn Wegelerstr 12 Bonn Germany D-53115 5 Bonn, Germany
Citazione:
P. Broekmann et al., "Atomic structures and dynamics of a Cu(100) electrode in dilute hydrobromic acid: An in situ STM study", J ELEC CHEM, 500(1-2), 2001, pp. 241-254

Abstract

The surface electrochemistry of Cu(100) in 10 mM hydrobromic acid electrolyte has been studied by means of cyclic voltammetry and in situ STM. In thepotential range between the onset of the anodic copper dissolution at positive and the hydrogen evolution at negative electrode potentials, the CV ofCu(100) in 10 mM HBr is characterized only by the double-layer charge. Within this potential regime a highly ordered (root2 x congruent to2)R45 degrees -superstructure is seen in the STM experiments assigned to specifically adsorbed bromide anions. No desorption of the bromide adlayer has been found in these STM experiments even at extremely negative potentials at the onset of hydrogen evolution. Therefore the bromide desorption potential is concluded to lie within the potential regime of massive hydrogen evolution at even more negative potentials. Adsorbed bromide induces a drastic restructuring and faceting of the surface topography depending on the applied potential. The driving force of this process is the formation of thermodynamically favored copper steps aligned parallel to close packed [100] directions ofthe bromide adsorbate. Dynamic processes like copper dissolution and deposition are also strongly influenced by the geometry of the (root2 x root2)R45 degrees bromide adlayer. Corrosion as well as deposition of copper material follows the close packed [100] directions of the bromide adsorbate. For moderate reaction rates an additional anisotropy between the [001]- and [010]-direction is observed due to the nonequivalence of two different kinds of bromide stabilized copper steps. The origin of these two kinds of steps is the phase relation of close packed adsorbate rows of adjacent terraces. The deposition of copper material does not only start at the lower but unusually, also at the upper sites of step edges leading to the formation of microfacets. Not only the growth of monoatomically high islands is observed but also a double-layer and multilayer growth of copper. (C) 2001 Elsevier Science B.V. All rights reserved.

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Documento generato il 04/07/20 alle ore 18:30:26