Simulated voltammograms

Figure 18.10 Three types of polarization curves typically manifested by simple Fe and Co porphyrins and cofacial metaUoporphyrins (simulated voltammograms).

The analysis of a cyclic voltammogram is simplified today, thanks to the availability of commercial software that produces simulated voltammograms [333,335]. Derivative cyclic voltammetry (DCV) is another improvement of the technique, where plots of di/dE versus E are obtained (i.e., the derivative of the... 

Figure 11 Simulated voltammogram (top) and adsorption isotherm (bottom) for the model with first neighbor shell exclusion and second neighbor shell interaction. Adsorption with an attraction of —0.5 kgT (dotted line) and a repulsion of +0.5 ksT (dashed line) compared to the case without second neighbor shell interaction (solid line)...

Figure 6.30 Simulated voltammograms for different radii of the sphere positioned in the center of the electrode. For the simulation the following parameters are used ...

Using a computer, carry out simulations of cyclic voltammetry for a quasireversible system. Let = 50 and Dm = 0.45, Take a = 0.5 and let the diffusion coefficients of the oxidized and reduced forms be equal. Cast your dimensionless intrinsic rate parameter in terms of the function ij/ defined in (6.5.5), and carry out calculations for ip = 20, I, and 0.1. Compare the peak splittings in your simulated voltammograms with the values in Table 6.5.2. 

Hgure 2 Simulated voltammograms showing the behavior observed for an organic molecule, e.g., acetophenone, that undergoes a following chemical reaction upon oxidation. The electrode is a 5 im radius platinum disk, and the rate constant for the homogeneous chemical reaction is 7.6 x 10 s . ... 

Fig. 14.3 Experimental ( solid lines) and simulated (open circles) voltammograms obtained when solid Fc particles are adhered to a 25 pm diameter Pt microdisk electrode in contact with [C4mim] [PFg] in the absence a) and presence (b) of 10 mM Fc. The simulated voltammogram open circles) was calculated using parameter values of iP = 0.0025 cm s , Z) = 3.0 x 10 cm s for both Fc and Fc, n= 1, a = 0.5, and an electrode area of 4.91 x 10 cm and normalized to the peak current in b) in order to demonstrate the shape and peak potential equivalence of voltammograms obtained from dissolved and adhered material. (iP, D, n, and a are standard heterogeneous electron-transferrate constants for the electrode reactions, diffusion coefficient, the number of electrons, and electron-transfer rate constant). Adapted with permission from Zhang et al.yAnal. Chem. 2003, 75, 2694-2702 [24]. Copyright 2013, American Chemical Society...

Fig. 14.7 Comparison of an experimental (solid lines) (scan rate 0.1 V s ) cyclic voltammogram obtained when an array of solid trans-Mn microparticles is adhered to a 1 mm diameter GC disk electrode (high-mass ease) that is placed in contact with [C4mim][PF6] and simulated data (open circle) that represents a cyclic voltammogram for the case where tra s-Mn is dissolved in bulk ionic liquid. The simulated voltammogram was calculated for a reversible one-electron-transfer process using D = 9.1x 10 cm s for both trans-Mn and [trans-Mn], electrode area 0.00857 cm, uncompensated resistance (R = 4,500 fl, and temperatine (T) = 293 K and has been normalized to the peak current of the experimentally obtained voltammogram in order to demonstrate the shape and peak potential equivalence of voltammograms obtained from adhered and dissolved material. Adapted with permissimi frtnn Zhang et al.. Anal. Cltem. 2(X)3, 75, 6938-6948 [23]. Copyright 2013, American Chemical Society...

An excellent fitting between the experimental and simulated voltammograms for the ORR was achieved when a follow-up homogeneous step (associated with the formation of the ion pairs between the imidazolium cation and the superoxide anion) was included. 

Figure 3.57. Simulated voltammogram (top) and adsorption isotherm (bottom) for (bi)sulfate adsorption on an fcc(lll) surface.

Simulated voltammograms in Fig 12 (curves 1 and 3) make evident the shift of the half-peak/half-wave potentials in negative direction with decreasing A (increasing v). The relationship for maximum shift in pure kinetic zone... 

They are impractical for the analysis of experimental data. A computational procedure has been worked out [129] to allow the comparison of experimental and simulated voltammograms. The analogous effects of kinetic and thermodynamic parameters on SW peaks and peak potentials can be derived for various electrode mechanisms as has been described for other voltammetric methods. 

The kinetic parameters for the reaction between Cp"Mn(CO)2(NCMe) and FPl were elucidated by comparison of experimental and simulated voltammograms over a wide tnnperature range and reaction conditions and resulted in k(25 - L3 x 10 M s , AH - 4.4 kcal/mol, and AS ... 

Figure 1. ECEE mechanism considaed in this work, with the standard redox potentials (E ) used in the simulated voltammograms.

Figure 2 Cyclic voltammograms showing the effects of cyclohexane at pH 7.4. Before cyclohexane polishing (left). After cyclohexane polishing (right). (a,b) Background (c,d) [dotted hne shown in (c) represents simulated voltammogram] 10 pM DA (e,f) acidic pH change (ApH = -0.4 units). Scan rate for all was 300 V/s. (Reproduced from Analytical Chemistry with permission [16]) Electrode carhon fiber radius was 6 pM.

Fig. 4.3 A simulated voltammogram of a one-electron reduction, highlighting the influence of the switching potential upon the height of the back peak.

Figure 7.7 shows three simulated voltammograms for the reduction of CI-C6H4-CN various scan rates. At a high scan rate (Fig. 7.7(a)), only one reversible voltam-metric wave is observed, at —1.96 V. This corresponds to the reduction and reoxidation of the CI-C6H4-CN species. Due to the high scan rate, the rate of the chemical step is slow on the timescale of the experiment, such that none of the CI-C6H4-CN formed on the forward scan reacts via the chemical process to form CsHs-CN. 

Figure 3.12 shows simulated voltammograms related to the paradigms A-la and A-lb, and following the mechanism depicted in Eqs. (3.9)-(3.11). Setting... 

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