Cyclic voltammetric curves

FIGURE 15.3 Cyclic voltammetric curve of 5 mM dopamine in PBS (pH 7.4) at a CNT electrode at 20mV s (Reprinted with permission from [16]. Copyright (1996) Elsevier.)... 

Figure 1. Solid lines - cyclic voltammetric curves for hydrogen and oxygen adsorption at the three Pt single crystal planes investigated determined from the pure (CO free) 0.1 M HC10, solution. Dotted lines - cyclic voltammetric curves of adsorbed CO oxidation (note the sensitivity for the CO oxidation curves has been ten fold attenuated. Sweep rate 50 mv/s.

FIGURE 14.6. Cyclic voltammetric curves for a AugiPtig/C catalyst (24 wt.%) on GC electrode (0.07 cm ) in 0.5M H2SO4 electrolytes saturated with O2 (solid curves) and Ar (dash curves). Scan rate 50 mV/s (from Ref. 35). 

Figure 4.18 Cyclic voltammetric curves for sphalerite electrode at natural pH in the presence of condition (BX 10 mol/L, KNO3 0.1 mol/L, scan rate 0.5 mV/s)...

Figure 6.2 Cyclic voltammetric curves for sphalerite compound electrode in buffer solution with different pH at 293K, KNO3 concentration of 0.5 mol/L and sweep rate of 20 mV/s...

Figure 8.2 Cyclic voltammetric curve of a solution of 0.15 mM (saturated) Cgo, 0.05 M TBAAsFg in dichloromethane [Pt electrode, scan rate 100 mV T = -55 °C, (V) vs ferrocene] [10].

Fig. 28 Reductive electrochemistry data for (72). Cyclic voltammetric curves for a 0.1-mM CH2CI2 solution of (72) at 100 mV s , glassy carbon as a working electrode, Pt-mesh as a counter electrode, and a Ag wire as a quasi-reference electrode, T = 25 °C, TBAPFs (0.1 M) was used as supporting electrolyte.

Fig. 1 Cyclic voltammetric curves of Pb electrode in 4.5 M H2SO4 solution [103].

Figure 13.13 (a) Cyclic voltammetric curves for the first three-electron reduction of (from top to bottom) 10H3, 10H2, 10H7+, and 106+... 

Figures 8.13 to 8.15 show several examples of cyclic voltammetric curves. The figures given are intentionally varied in complexity. Computer simulation of these cyclic voltammograms can, however, be carried out (Gosser, 1993).23...

FIGURE 3. Cyclic voltammetric curves for the tetracobaltcarbonyl cluster in thf containing 0.1 M tetrabutylammonium perchlorate. Sweep rate, 200 mVs-1. The inset shows the scans of the first (0/—1) redox couple at 1000,500,200 and 100mVs-1. Reprinted with permission from Reference 27. Copyright 1986, American Chemical Society... 

Figure 28.13 ECL generation by the step technique. The Ag/AgCl, KC1 (satd.) reference is -0.045 V vs. SCE. (a) Cyclic voltammetric curve (0.593 mAf rubrene in benzo-nitrile with 0.1 M TBAP) (b) working electrode potential program (c) emission intensity versus time.

Several criteria can be used for the analysis of the cyclic voltammetric curve to determine the reversibility of the redox system investigated ... 

In Fig. 7.7, cyclic voltammetric curves are shown of the oxidation of sodium dithionite at a gold electrode (curves 1,4), at a CoTSPc-modihed gold electrode (curves 2, 5) and at a CoTSPor-modihed gold electrode (curves 3, 6) for two different sodium dithionite concentrations. Several observations indicate electrocatalytic behaviour. First, the voltammetric waves are shifted towards less-positive potentials. This means that less... 

Cyclic Voltammetric Behavior of the PPy-GOD Film. Figure 1 shows the cyclic voltammetric curves of a PPy-GOD film (4000 A) in phosphate buffer solution with pH 7.4 at different scan rates. Both anodic and cathodic peaks should correspond to the redox reactions of PPy chains. The peak potentials, which were recorded at the scan rate of 200 mV/s, were -380 mV and -200 mV for cathodic and anodic peaks, respectively. This is similar to the potential shifts of the PPy film doped with large anions (27) such as poly(p-styrenesulfonate). Enzyme protein molecules are composed of amino acid and have large molecular size, which can not move out freely from the PPy-GOD film by the application of the reduction potential. In order to balance the charge of the Pfy-GOD film, cations must move into the film, and redox potentials move toward a more negative potential. This behavior is different from the one observed for the PPy-GOD film, which was prepared in the solution of GOD... 

Figure 1. Cyclic voltammetric curves of PPy-GOD film (4000 A) with different scan rates in 0.05 M phosphate buffer (pH 7.4) solution. Scan rates (mV/s) (1) 10, (2) 20, (3) 50, (4) 100, and (5) 200.

Similar cyclic voltammetric curves were also obtained in experiments performed at a slightly higher temperature, i.e., 333 K, under otherwise the same conditions (see lower panel, Figure 39), except for the presence of a small peak b at 0.75 V during the first scan in the negative direction (dotted line), which disappeared after the first cycle, and for what seems to be a surface-bound redox couple at about 2.0 V (d,d ) also observed by other workers in liquid nonaqueous solutions [64,65],... 

Figure 42 First (dotted line) and second (solid line) cyclic voltammetric curves for the oxygen-contaminated Ag specimen described in the caption to Figure 40 (upper curve) in LiC104(PE0) recorded at 333 K. Other conditions are specified in the caption to Figure 39.

Chemisorption of hydrogen on platinum metals is a reversible process as demonstrated by the symmetry of the cyclic voltammetric curves (- voltammetry). The voltammetric behavior of these systems depends on the... 

Fig. 57 The effect of holding time on cyclic voltammetric curves during the first stage of PEVD at 550°C.

From two such electrodes. Foe /Foe and BCr /BCr, suggested by Gritzner and Kuta [63] as equally good reference electrodes in nonaqueous electrochemistry, the Foe /Foe electrode is preferred in the use of mixed solvents, particularly with water as one of the components of the mixture, since the solubility of BCr in water is very low (see, however, [242]). Also the behavior of the Foe/Foe electrode in water is not ideal, because of poor solubility of Foe [62] in this solvent. Sinee the product of electroreduction. Foe, is to some extent accumulated on the electrode surface, cyclic voltammetric curves starting with the electroreduction of ferricinium ions exhibit an anodic current which is greater than the diffusion-limited one. Nevertheless, the error which results from the Foe adsorption should not be significant, especially in mixtures where the water eontent is not very high. 

Cyclic-voltammetric curves (360, 362-367) in the potential range 1.2 to 0.4 V in acid and alkaline solutions show (Fig. 41) that although the volt-ammagram in acid media is featureless, a well-developed reversible peak is noticed in alkaline solutions just prior to oxygen evolution (360, 364). The voltammetric behavior of RuOj electrodes has been attributed (360, 368) to reversible oxidation-reduction through a mechanism involving proton exchange with the solution ... 

Fig. 16. Slow cyclic voltammetric curves with CPP, in 4 M (a) and 10 m (b) electrolyte acids as indicated, second cycle, Vs = 1 mV/s, 25 °C. The voltage scan was reversed at a current density of 5 mA/cm. Potential t/j vs. Hg/Hg2S04/l m H2SO4.

During the electrolysis it is advisable to obtain some indication of what is going on in the cell. An indicator microelectrode in the electrolytic cell is valuable in order to follow the progress of the electrolysis and to detect intermediates. An intermediate more easily reducible than the substrate, for example, may be detected as a small prewave, and its halfwave potential or other voltammetric characteristics used for its identification. Polarographic or cyclic voltammetric curves measured during the electrolysis also present a means of monitoring the process. The combination of electrochemical and optical tech-... 

Figure 4 Cyclic voltammetric curves for (A) BDD and (B) BDD/Ir02 (F = 1.3, sample prepared at 450 °C) in 0.5 M H2SO4. Scan rate 3Vs T = 25°C.

Figure 8(a) shows a cyclic voltammetric curve obtained at BDD electrode in 0.5 M H2SO4. The fact that the separation between the cathodic and the anodic peaks (AEp) is very high (about 0.9 V) indicates that the Q/H2Q system is irreversible at the boron-doped diamond electrode. Furthermore, the apparent equilibrium redox potential of the couple Q/H2Q(Eo = 0.65 V) is much closer to the anodic peak potential than to the cathodic one. 

Figure 20 Cyclic voltammetric curves for three Ru02-modified BDD electrodes, 1.2 x 10 and 6.0 X 10 " molecules, cm (A), and 2.65 x 10 molecules, cm (B), recorded in 1 M H2SO4. Scan rate 300mV s Electrode (geometric) area = 0.785 cm. (Photograph (A) reprinted with permission from A. De Battisti, S. Ferro, M. Dal Colle. J. Phys. Chem. B, 105, 1679. Copyright 2001, The American Chemical Society.)...

Figure 22 Cyclic voltammetric curves for a BDD/RUO2 electrode with 1.2 X 10 Ru02 molecules, cm, in 0.01 M HCIO4/XM NaCl/(4 — x) M NaC104. Scan rate lOOmVs h Electrode (geometric) area = 0.785 cm. ...

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