Voltammograms curve

Fig. 5.14 Peak voltammogram (curve 1, j t) — E dependence) and convoluted voltammogram (curve 2, F(t) — E dependence) for the reversible case...

Pyrrhotite is one of many sulphides which display collectorless flotation resulting from the formation of sulphur on the mineral surface (Hamilton and Woods, 1981 Heyes and Trahar, 1984 Hodgson and Agar, 1984). The anodic scan section of cyclic voltammetry for pyrrhotite electrode in pH = 2.2, 4.7, 7.0, 8.8, 11, 12.1, 12.7 buffer solutions respectively, is presented in Fig. 2.23. The cyclic voltammograms curve at pH = 8.8 is also presented in Fig. 2.23. It can be seen from Fig. 2.23 that anodic current peak emerges at about -0.1—0 V when pH < 11. As pH increases, the peak moves to the left. This peak may correspond to the following reactions ... 

The electrochemical mechanism of cupric sulphate activating sphalerite has been studied. The measured cyclic voltammogram curves in aqueous solution at different pH with sphalerite compound electrode are shown as solid lines in Fig. 6.1. 

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. 

In Fig. 7.55, the SWV and SWVC curves for an EE mechanism with identical values of the surface rate constants lc /ic = 1 are plotted. As can be inferred, the Square Wave Voltammograms (curves a and b) present a maximum value for the peak currents (quasi-reversible maximum, QRM, see Sect. 7.7.1.4) forij = lc2 = 1, and a splitting is observed for = lc2 = 1.5 with much lower peak height. For 1c-... 

Figure 3.11 Square-wave voltammograms for TNT solutions of increasing concentration from 1 to lOppm (curves b-k), along with the background voltammogram (curve a) and resulting calibration plot (inset). (Reproduced with permission from Ref. 11.)...

Figure 6.2.3 Effect of double-layer charging at different sweep rates on a linear potential sweep voltammogram. Curves are plotted with the assumption that Cd is independent of E. The magnitudes of the charging current, ic, and the faradaic peak current, /p, are shown. Note that the current scale in (c) is lOX and in (d) is lOOX that in (a) and (b).

The cyclic voltammogram curves of formaldehyde oxidation are presented in Fig. 1. In the anodic sweep of curve (a), the well-defined anodic peak at approximately +0.78 V (vs. SCE) is attributable to the oxidation of CO to CO2 on the Pt surface [3]. In the reverse sweep, an anodic peak was observed at approximately +0.51 V (vs. SCE) due to the complete oxidation of HCHO to... 

Fig. 12 Cyclic voltammograms (curves in a and b) and the corresponding convoluted semiintegrals (curves In c and d) for the reduction of tert-butyl-perbenzoate (a and c) and its p-acetyl derivative (b and d) in DMF/0.1 M NBU4CIO4 (currents in a and b normalized to at various scan rates. (Reprinted with permission from Ref [84], Copyright 1999 American Chemical Society.)...

Fig. 5.7 a Schematic representation and thrombin recognition by an electrochemical aptamer-based sensor and b voltammogram curves of the E-AB sensor before and after deposition of 40 nM of thrombin. Reproduced with permission from [46]... 

Figure 3. Transformation of voltammograms curves while titration of NaCl-KCl-K2TaF7 (0.127 m/o) melt with sodium oxide. V=0.1 V s T=750 °C,...

See color insert.) (a) Graphene composite film with polypyrrole deposited for 120 sec. Inset shows SEM image at the observation area. White bar = 100 nm. (b) Cyclic voltammogram curves for pure graphene film, (c) Graphene with polypyrrole deposited for 120 sec in KCl solution between -0.4 and 0.6 V versus SCE at scan rates of 0.01, 0.02, 0.05, 0.1, and 0.2 V/sec. Source Davies, A. et al. 2011. Journal of Physical Chemistry C, 115,17612-17620. With permission.)... 

As discussed in Chapter 5, LiFeP04 is a widely used phosphate positive electrode. In this section, other kinds of phosphates, mostly based on LiMnP04, are discussed. The complex phosphate Li3Fe2(P04)3 has a sodium (Na) Super Ionic CONductor (NASICON) structure. The cyclic voltammogram ( ) curve shows two plateaus during the charge and discharge processes, at 2.80 and 2.65 V, with a reversible capacity of up to 1.5-1.6 Li per unit. Since very little is known about this material, it will not be discussed further. 

Fig. 12 a Cyclic voltammograms curves of varied films at a scanning speed of 20 mV/s b galvanostatic charge to discharge curves of varied films at a current density of 500 mA/g [72] (Reprinted with permission from Ref. [72] Copyright (2015) by Springer)... 

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