Voltammograms CV

Other techniques such as cyclic voltammogram (CV), atomic force morphology (AFM), and scanning force morphology (SFM) have also been used for... 

CV. See Cyclic voltammogram (CV) Cyanate resins, phenolic, 418 Cyclic dimers, 153... 

Cyclic voltammetry is perhaps the most important and widely used technique within the field of analytical electrochemistry. With a theoretical standard hydrogen electrode at hand, one of the first interesting and challenging applications may be to try to use it to make theoretical cyclic voltammograms (CVs). In following, we set out to do this by attempting to calculate the CV for hydrogen adsorption on two different facets of platinum the (111) and the (100) facets. 

Before the measurement of HOR activity, a pretreatment of the alloy electrode was carried out by potential sweeps (10 V s ) of 10 cycles between 0.05 and 1.20 V in N2-purged 0.1 M HCIO4. The cyclic voltammograms (CVs) at all the alloys resembled that of pure Pt. As described below, these alloy electrodes were electrochemically stabilized by the pretreatment. Hydrodynamic voltammograms for the HOR were then recorded in the potential range from 0 to 0.20 V with a sweep rate of 10 mV s in 0.1 M HCIO4 saturated with pure H2 or 100 ppm CO/H2 at room temperature. The kinetically controlled current 4 for the HOR at 0.02 V was determined from Levich-Koutecky plots [Bard and Faulkner, 1994]. 

Except for very electron-rich donors that yield stable, persistent radical cations, the ox values are not generally available.64 Thus the cation radicals for most organic donors are too reactive to allow the measurement of their reversible oxidation potentials in either aqueous (or most organic) solvents by the standard techniques.65 This problem is partially alleviated by the measurement of the irreversible anodic peak potentials E that are readily obtained from the linear sweep or cyclic voltammograms (CV). Since the values of E contain contributions from kinetic terms, comparison with the values of the thermodynamic E is necessarily restricted to a series of structurally related donors,66 i.e.,... 

Cyclic Voltammetry. Figure 1 shows the cyclic voltammograms (CV s) determined for the three crystal planes in a clean (CO free)... 

To leam how to test for electro-reversibility from simple diagnostie tests concerning the cyclic voltammogram (CV) peak currents and potentials,... 

Figure 6.13 shows a voltammogram for a simple solution-phase couple such a plot is known as a cyclic voltammogram (CV). The adjective cyclic arises from the closed loop drawn within the plot. The shape of the CV shown in Figure 6.13 is typical for a couple that is wholly reversible in the thermodynamic sense other simple diagnostic tests for electro-reversibility are listed in Table 6.3. 

Wfe can be satisfied that the variables we have (e.g. A, D, etc., as above) are accurate if they allow us to model a system precisely. Vie say that the variables fit the data. Figure 10.1 shows a cyclic voltammogram (CV), with superimposed on this current-potential data simulated with the DigiSim package (as described in more detail below). The fit between theory and experiment is seen to be good, so we say that the derived variables fit the data. 

Cyclic voltammogram (CV) A plot of current (as y ) against potential (as x ) obtained during a voltammetric experiment in which the potential is ramped twice, once forward to the switch potential and then back again. 

The comparison of the voltammetric characteristics of PWig and P2W18 is useful to highlight the peculiarities of the former complex. Figure 21 shows in superimposition the cyclic voltammograms (CVs) of the two complexes in a pH 0.3 sulfate medium. The potential domain was selected to avoid any deleterious derivatization of the electrode surface [28]. Furthermore, such domain is the most useful for elucidation of electrocatalytic processes. Here, the voltammetric pattern is restricted to the first three waves observed for PWig in this medium. In... 

Fig. 21 Cyclic voltammograms (CVs) run on 5 M solutions of the relevant polyoxometalates scan rate ...

Corresponding to a cyclic voltammogram (CV), recorded at a glassy carbon electrode (GCE) immersed into a 1.0 mM Cu + solution in acetic acid/sodium acetate... 

In Fig. 9.5, curve (a) is the cyclic voltammogram (CV) for the oxidation of tri-p-anisylamine (TAA) in 0.1 M Et4NCl04-AN, and curves (b) and (c) are the absorbance-potential curve and its derivative curve, respectively. They were obtained using an OTE with a vapor-deposited platinum film [8]. The excellent agreement of curves (a) and (c) shows that the reaction in the CV is purely the oxidation and re-reduction of the TAA. However, the two curves are different in that the peak current for curve (a) is proportional to the square root of the voltage sweep rate, while the peak height of curve (c) is inversely proportional to the square root of the voltage sweep rate. 

Figure 9 shows a cyclic voltammogram (CV) of hexacyanoferrate(III) (Fe(III)) in water observed at a gold microelectrode (8 fim wide x 33 fim long x 0.2 fim thick). A cathodic current at 200 mV corresponds to reduction of Fe(III) to Fe(II). At a micrometer-sized electrode, mass transfer of a solute in water to the electrode proceeds very efficiently owing to hemispherical diffusion of the solute. This is proved by a characteristic sigmoidal current-potential curve in the CV, different from a peak current observed at a millimeter-size electrode (linear diffusion) [32,64]. Using... 

Figure 18. Cyclic voltammogram (CV) of a Pt electrode on an MEA. Shown are the associated electrochemical reactions at difference electrode potentials. Notice how the electrode potential changes as the cell starts from air/air conditions (diamond-tailed arrows) and stops from H2/air conditions (dot-tailed arrows), respectively. Experimental conditions 25 °C, 20 mV/s, 0.4 mgpt/cm2 loading.

Figure 14. Dependence of the current density difference Ai between anodic and cathodic peak currents of the cyclic voltammograms (CVs) on the scan rate v for carbon specimens A (o), B ( ), and C (A). Reprinted from Ref. 17, (2006), with permission from Elsevier.

---