Copper voltammogram

Fig. 10.3. General electrochemical performance of MPA-Gly-Gly-His modified electrodes for the detection of Cu2+ ions. Cu2+ ions are complexed to Gly-Gly-His in the accumulation process and are electrochemically reduced to Cu(0) to give UPD Cu. (a) Cyclic voltammograms of MPA-Gly-Gly-His modified electrodes in 50 mM ammonium acetate (pH 7.0) and 50 mM NaCl at 25°C at a scan rate of lOOrnVs-1 (i) before accumulation of metal ions and (ii) after accumulation in 46 nM Cu2+ in 50 mM ammonium acetate (pH 7.0) for 10 min. Multiple cycles in the copper voltammogram illustrate stable electrochemistry, (b) Cathodic Osteryoung square wave voltammograms of MPA-Gly-Gly-His modified gold electrodes in 50 mM ammonium acetate (pH 7.0) and 50 mM NaCl (i) before accumulation of metal ions and (ii) after accumulation in 46 nM Cu2+ in 50 mM ammonium acetate (pH 7.0) for 10 min. Reprinted from Ref. [12]. Copyright (2005) with permission from Elsevier.

Figure 34. Voltammograms for T1 deposition onto a copper single crystal in the presence (a) and absence (b) of traces of oxygen. Inset electrochemical cell. (From Ref. 120, with permission.)...

Melendres et ai (1991) reported the in-situ study of the electrode/oxide and oxide/electrolyte interfaces for a copper electrode in pH 8.4 borate buffer under potential control. The grazing-angle incidence arrangement employed by the authors is shown in Figure 2.81(a) and a cyclic voltammogram of the Cu electrode in the buffer is shown in Figure 2.81(b). 

Cyclic Voltammogram of the copper tri-crystal in a 0.1 mM 5b, 1 mM HC1 solution. Scan Rate - 5 mV/sec. Ag/AgCl Reference Electrode. Gold Wire Auxiliary Electrode. Sbz03 in HCt Solution. 

Figure 4.9 Cyclic voltammogram for the upd of copper on Au(lll) the electrolyte is an aqueous solution of 0.05 M H2SO4 and 10-3 M CUSO4 courtesy of D. Kolb, Ulm.

To obtain structural information on the adsorption sites, single crystal electrodes must be used. As an example we consider the upd of copper on Au(lll), whose cyclic voltammogram we have discussed previously (Fig. 4.9). The adsorption and desorption peaks are very... 

Figure 1. Cyclic voltammograms in MeCN(0.1M tetra-ethylammonium perchlorate) for the oxidation of (a) a copper electrode, (b) 3 mM "OH at a glassy carbon electrode, (c) 0.5 mM "OH at a copper electrode, and (d) 3 mM "OH at a copper electrode. Scan rate, 0. IV s"1 electrode area, 0.08 cm2 copper electrode prepared by electroplating Cu(C104) onto a glassy carbon electrode (GCE). ...

Electrochemical mechanism of copper activating marmatite is investigated by using voltammetric method. The voltammogram of the marmatite electrode in the presence of 10 mol/L Cu is presented in Fig. 6.7. It can be seen that in the presence of cupric ion marmatite surface exhibits the electrochemical character of activation products. In the light of E h-pH diagram of the CU-S-H2O system... 

They found that a Cu electrode, pretreated by immersing it in a 0.1M BTA solution for 15 seconds, inhibited the 0 reduction reaction initially and that on subsequent cycles the currents Increased to that of bare Cu in a short time. A similar effect was observed when a Cu electrode was cycled in a ImM solution of BTA. They discovered that a solution of 0.1M BTA produced a lasting effect, indicating that a reservoir of BTA is necessary for continuous protection of the copper against corrosion. We found that bare Cu gives the same voltammogram in the 0 reduction region in both acetate buffer and phosphate buffer therefore, McCrory-Joy et. al. s results can be directly compared to the results reported here. 

Figure 6.2-7 Cyclic voltammogram of CuCI in acidic [BMIMj cr/AICIs on Au(l 11) three UPD processes are observed, correlated with decoration of Au steps by copper, formation of an 8x8 superstructure followed by a Cu monolayer. Before the bulk deposition a second monolayer grows together with clusters...

The usefulness of this kind of analysis is illustrated in Fig. 2.11 where the square wave voltammograms for azurite, smalt, and two samples from the frescoes painted by Palomino (1707) in the Sant Joan del Mercat church in Valencia (Spain) are shown. Copper pigments yield a unique stripping peak at —0.05 V, whereas cobalt pigments produce a main anodic peak at +0.02 V, accompanied by overlapping... 

Electrochemical methods can be applied to the determination of the composition of solid phases as well as mixtures of solids [224-228], The first situation is illustrated in Fig. 4.1, where cathodic voltammograms of CuS, CuSe, and a solid phase of composition CuSeoASo.e reported by Meyer et al. [227] are shown. This last can be described as a solid solution formally regarded as a copper sulfide, in which 40% of sulfide ions have been replaced by selenide ions. The new phase produces a voltammetric peak at a potential intermediate between those for CuS and CuSe. 

Fig. 6.3 CycUc voltammogram (1st cycle) of sterling silver (92.5% Ag, 7.5% Cu) in 0.5M NaCH3COO, pH 4, v = lOmV/s copper and silver oxidation peaks, indicating surface passivation in presence of Ata (3-amino,1,2,4-triazole) (from [304])...

The electrochemical and chemical behavior of rotaxane 7 + was analyzed by CV and controlled potential electrolysis experiments.34,35 From the CV measurements at different scan rates (from 0.005 to 2 V/s) both on the copper(I) and on the copper(II) species, it could be inferred that the chemical steps (motions of the ring from the phenanthroline to the terpyridine and vice versa) are slow on the timescale of the experiments. As the two redox couples involved in these systems are separated by 0.7 V, the concentrations of the species in each environment (tetra- or pentacoor-dination) are directly deduced from the peak intensities of the redox signals. In Fig. 14.13 are displayed some voltammograms (curves a-e) obtained on different oxidation states of the rotaxane 7 and at different times. 

A second electrolysis at —0.3 V restores the initial red solution. The voltammogram (curve (e)) performed immediately after the reductive electrolysis of the redox couple of 7"+ is invariant with time. As all the pentacoordinate copper(I) species formed electrochemically are quantitatively transformed into tetracoordinate copper(I) species during the electrolysis, we can give a lower limit of 10 4 s 1 for the rate constant of the chemical reaction. The residual signal at —0.03 V simply reflects an incomplete electrolysis. 

The redox properties of dinuclear copper(II) complexes have received extensive attention using cyclic voltammetry measurements, and it was recognized in the early literature that the two copper(II) ions could be reduced to copper(I) at the same potential or at different potentials (Section 53.3.7).30,934,1021,1022 In either case the reduction requires a two electron process and if the E° values are well separated may result in the observation, under favourable circumstances, of a two-peaked cyclic voltammogram (Figure 61b), as in... 

By contrast, the cobalt and iron doped electrodes form a perfectly reversible redox system showing voltammograms which are independent of film thickness. It was suggested that differences arose from more facile electron hopping in the case of four coordinate copper(II) than for five or six coordinate M11/111 (M = Co, Fe). Electrodes doped with manganese(II) or zinc(II) gave no response. 

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