Copper, underpotential deposition

Michaelis R, Zei MS, Zhai RS, Kolb DM (1992) The effect of halides on the structure of copper underpotential-deposited onto Pt(lll) a low-energy electron diffraction and X-ray photoelectron spectroscopy study. J Electroanal Chem 339 299-310... 

Figure 23. In situ X-ray absorption spectrum for half a monolayer of copper underpotentially deposited on a bulk Pt (111) electrode pretreated with iodine.

EXAFS results, Cu atoms locate on the top of Pt atoms. Experimental and theoretical EXAFS studies were carried out for Cu underpotential deposition on Pt(lll) in a 0.1 M H2SO4 -1- SQ/iM Cu " solution, giving the position of copper underpotential deposition at three hollow sites of Pt(lll), which is partially positively charged. ... 

One of the most important processes in metallurgy is copper deposition. Galvanoplastic conditions imply a copper-acid bath over a pre-multilayer of copper from a copper-alkaline cyanide bath. The study of copper underpotential deposition on platinum is of special interest in electrochemistry in spite of its catalytic properties being rather poor with respect to fuel cell applications [101-104]. The mechanism of copper deposition and the presence of copper(I) ions as an intermediate have been... 

Chierche et al. [110] were first to study copper underpotential deposition on poly crystalline palladium. They assigned different copper voltammetric peaks to the contributions of the different low Miller index crystallographic planes of palladium. They also proposed that copper underpotential deposition obeys a Temkin-type isotherm with a saturation charge density of 420 pC cm 2. The electrochemical response on polyfaceted palladium is observed in Figure 9.6. 

On the Pd(lll) single crystal, iodide adsorption leads the ( /3 x y/3) R30° I superlattice at potentials lower than 0.80 V at pH =10, whereas on Pd(100), a c(2 x 2) I superlattice is found [111]. Copper underpotential deposition on noble metals is a relatively slow process, and the electrochemical response is strongly dependent on the potentiodynamic perturbation, because of... 

Copper underpotential deposition on palladium in 0.5 M NaC104, 10 3 M HC104, and 0.01 M CuS04 in the presence of little amounts of iodide in solution (such as 10-6 M) produces drastic changes in the voltammetric profiles. In Figure 9.7, the repetitive voltammetric profile at 0.01 V s 1 of the process in 3 x 10 1 M KI can be seen. 

Blum L, Abruna FI D, White J, Gordon J G, Borges G L, Samant M G and Melroy 1986 Study of underpotentially deposited copper on gold by fluorescence detected surface EXAFS J. Chem. Phys. 85 6732-8... 

Copper electrodeposition on Au(111) Copper is an interesting metal and has been widely investigated in electrodeposition studies from aqueous solutions. There are numerous publications in the literature on this topic. Furthermore, technical processes to produce Cu interconnects on microchips have been established in aqueous solutions. In general, the quality of the deposits is strongly influenced by the bath composition. On the nanometer scale, one finds different superstmctures in the underpotential deposition regime if different counter-ions are used in the solutions. A co-adsorption between the metal atoms and the anions has been reported. In the underpotential regime, before the bulk deposition begins, one Cu mono-layer forms on Au(lll) [66]. 

Most recently, we have been able to obtain the in situ surface EXAFS spectrum of a half-monolayer of underpotentially deposited copper on a bulk Pt(lll) single crystal pretreated with iodine. The spectrum shown in Fig. 23 is a bit noisy (due to limited number of scans) but at least five well-defined oscillations can be observed. Preliminary data analysis indicates that the copper adatoms sit on threefold hollow sites with copper neighbors at 2.80 0.03 A. This distance is very close to the Pt—Pt distance in the (111) direction and indicates the presence of a commensurate... 

Due to the experimental difficulties involved, there have been only three reports of XSW measurements at electrochemical interfaces. Materlik and co-workers have studied the underpotential deposition of thallium on single-crystal copper electrodes under both ex situU9 and in situ120 conditions. In addition, they report results from studies in the absence and presence of small amounts of oxygen. 

Our work was generously supported by the Materials Science Center at Cornell University, the National Science Foundation, the Office of Naval Research, the Army Research Office, and the Dow Chemical Company. Special thanks to Dr. Michael J. Bedzyk (CHESS) and to Dr. James H. White as well as to Michael Albarelli, Mark Bommarito, Dr. Martin McMillan, and David Acevedo. The work on the copper and silver underpotentially deposited on gold... 

We have previously employed such techniques in the study of iodide adsorption onto Pt(lll) electrodes (2 5 > as well as in the in-situ structural characterization of underpotentially deposited copper and silver on Au(lll) electrodes. (23.)... 

The underpotential deposition of T1 on Cu(l 11) has been examined by Shannon et al. [133] under static conditions, and Richmond and Robinson in the time domain [117]. A large mismatch between the copper and the thallium lattice constants makes it an interesting case for comparison with the Tl/Ag(lll) SH study described above [122] where the lattice constants are more closely matched and the overlayer has been shown to form in an ordered manner. From strictly geometrical considerations, the silver lattice is able to accommodate a thallium overlayer without buckling. On the copper substrate, a close-packed thallium overlayer must be either buckled or rotated with respect to the substrate lattice. 

Lead and mercury are deposited as micron-sized clusters, predominantly at intercrystallite boundaries [105] so does lithium from the polyethylene oxide solid electrolyte. What is more, Li intercalates into the sp2-carbon [22, 138], Thus, observations on the Li intercalation and deintercalation enable one to detect non-diamond carbon on the diamond film surface. Copper is difficult to plate on diamond [139], There is indirect evidence that Cu electrodeposition, whose early stages proceed as underpotential deposition, also involves the intercrystallite boundaries [140], We note that diamond electrodes seem to be an appropriate tool for use in the well-known electroanalytical method of detection of traces of metal ions in solutions by their cathodic accumulation followed by anodic stripping. The same holds for anodic deposition, e.g. of, Pb as PbCh with subsequent cathodic reduction [141, 142], Figure 30 shows the voltammograms of anodic dissolution of Cd and Pb cathodically predeposited from their salt mixtures on diamond and glassy carbon electrodes. We see that the dissolution peaks are clearly resolved. The detection limit for Zn, Cd, and Pb is as low as a few ppb [143]. 

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