Copper dissolution in the presence of a binary 2D-compound : CuI on Cu(100)
Exposing a Cu(100) electrode surface to an acidic and iodide containing electrolyte (5 mM H2SO4/1 mM KI) leads to the formation of an electro-compressible/electro-decompressible c(p X 2)-I adsorbate layer at potentials close to the onset of the copper dissolution reaction. An increase of mobile CuI...
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Published in | Journal of applied electrochemistry Vol. 36; no. 11; pp. 1241 - 1252 |
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Main Authors | , , |
Format | Journal Article |
Language | English |
Published |
Heidelberg
Springer
01.11.2006
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Subjects | |
Online Access | Get full text |
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Summary: | Exposing a Cu(100) electrode surface to an acidic and iodide containing electrolyte (5 mM H2SO4/1 mM KI) leads to the formation of an electro-compressible/electro-decompressible c(p X 2)-I adsorbate layer at potentials close to the onset of the copper dissolution reaction. An increase of mobile CuI monomers on-top of the iodide modified electrode surface causes the local CuI solubility product to be exceeded thereby giving rise to the nucleation and growth of a laterally well ordered 2D-CuI film at potentials below 3D-CuIbulk phase formation. Step edges serve as sources for the consumption of copper material upon compound formation leading to accelerated copper dissolution at the step edges. The 2D-CuI film exhibits symmetry properties and nearest neighbor spacings that are closely related to the (111) lattice of the crystalline CuIbulk phase. Intriguingly, the 2D-CuI film on Cu(100) does not act as an efficient passive layer. Copper dissolution proceeds at slightly higher potentials even in the presence of this binary 2D-compound via an inverse step flow mechanism. Further dissolution causes the nucleation and growth of 3D-CuI clusters on-top of the 2D-CuI film. This several nanometer thick 3D-CuIbulk phase passivates the electrode against further dissolution. Characteristically, the formation/dissolution of the 3D-CuIbulk phase reveals a significantly larger potential hysteresis of about DeltaE = 320 mV while the appearance/disappearance of the 2D-CuI film is reversible with a potential hysteresis of only DeltaE = 20 mV. |
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Bibliography: | ObjectType-Article-2 SourceType-Scholarly Journals-1 ObjectType-Feature-1 content type line 23 |
ISSN: | 0021-891X 1572-8838 |
DOI: | 10.1007/s10800-006-9183-2 |