Anodic current-voltage curves with

Figure 3. Anodic current-voltage curves in aqueous sodium hydroxide. Key A, with Hyamine 2389 and B, with Hyamine 2389 plus 8.76 X 10 M thiourea.

Coulometric determinations of metals with a mercury cathode have been described by Lingane. From a tartrate solution, copper, bismuth, lead, and cadmium were successively removed by applying the appropriate cathode potential, which was selected to correspond to a region of diffusion-controlled current determined from current-voltage curves with a dropping mercury electrode. With a silver anode, iodide, bromide, and chloride can be deposited quantitatively as the silver salt. By controlling the anode potential, Lingane and Small determined iodide in the presence of bromide or chloride. The separation of bromide and chloride, however, was not successful because solid solutions were formed (Section 9-4). 

The metal is determined by measuring the current-voltage curve with applying an anodic (positive) voltage sweep and recording the anodic dissolution current (i.e., reoxidation). This method is above all suitable for the determination of Bi, Cu, Tl, Pb, Sn, Cd, Zn, and Hg, the latter by the use of a gold electrode. This method has been applied to the determination of different metal ions in body fluids, e.g., Pb [15,16], Tl [17], Cu [18], and Hg [10]. 

Several types of experimental magnesium-air cells were tested. These cells varied in their size (the working area of the air electrodes used) [10]. The current-voltage curves of an experimental Mg-air cell with two air electrodes (Sair = 80 cm2) with pyrolyzed CoTMPP catalyst and sandwich-type Mg anode (MA8M06) operating in NaCl-electrolytes with different concentrations are presented by Figure 2. 

Fig. 7. Current voltage curves of the anodic oxygen evolution at different temperatures in 30 wt% KOH at nickel anodes with coatings containing cobalt oxides (a) La0 5Co -.EaC), (b) Nin2, CouxLaO , (c) Co,04, and, for comparison, (d) RuO..

FIG. 31. (a) Current voltage curve of the PbOi anode in electrolytes without and saturated with benzene and (b) potential dependence of current efficiency of benzene oxidation. 

It is therefore intriguing to understand what is the particular role of the platinum/electrolyte interface in the Kolbe synthesis favoring that reaction path—Eqs. (39a)-(39c)—which is thermodynamically disfavored and unlikely to occur. A closely related reaction whose kinetics are easier to investigate with conventional electrode kinetic methods is the anodically initiated addition of N3 radicals to olefins, discovered by Schafer and Alazrak (275). The consecutive reactions, which follow the initial generation of the reactive intermediate, an Na radical, are somewhat slower than that of the Kolbe radicals, so that their rate influences the shape and potential of the current voltage curves which can be evaluated in terms of reaction rates and rate laws. 

It is important to realize that the actual potential of the two electrodes is not fixed with respect to any reference electrode. Consequently, in Figure 3.43A the AE increment is free to move on the potential axis. It locates itself at whatever potential is necessary for the current at the anode to balance the current at the cathode. This means that the AE increment will always straddle the potential at which the current voltage curve shows zero current (intercepts the potential axis). 

Figure 1.10. Tafel plot for cathode and anode branches of the current-voltage curve [19]. (From Wang J. Analytical electrochemistry. 2006 Wiley-VCH. Reproduced with permission.)...

Figure 6.13. (a) Apparatus Tor stripping analysis, (b) Curve A Current-voltage curve for anodic stripping of cadmium. Curve B Residual current curve for blank. Reprinted with permission and adapted from R. D. DeMars and 1. Shairf, Anal. Chem. 29,182S (1957). Copyright by the American Chemical Society... 

Figure 24. (a) Experimental cyclic voltammogram of formic acid oxidation on Pt (111) with external resistance430 1. Electrolyte 0.05 M HCOOH, lO M HCIO4. Scan rate 5 mV/s. (After Strasser et al. (b) Calculated cyclic voltammogram and stationary current-voltage curve for the formic acid model [Eq. (15)]. A smaller trppjggjjWas chosen than the one used in Fig. 22(a). The anodic and cathodic scans are indicated by arrows. The dashed line shows the portion of the stationary state curve that corresponds to unstable steady states. (After Strasser et al. with permission of the authors.)... 

Electrons are delivered (cathode) or accepted (anode) by the electrode. At electrodes with a small area (<0.1 cm ) the electrolysis can be conducted on a microscale. From the current/voltage curves obtained, valuable information can be obtained with regard to the reaction conditions for carrying out preparative scale electrolysis. The electrolysis is conducted in a cell, which is equipped with three electrodes ... 

Figure 4. Current-voltage curves for 50 50 mm anode-supported single cells with a YSZ electrolyte applied by sol-gel technique and with an LSCF-type cathode as a function of the temperature (fuel gas H2 (3% H2O) = 1000 ml/min, oxidant air = 1000 ml/min).

Fig. 31 Electrochemical model for the delamination of an organic coating from galvanized steel with a defect down to iron in terms of the current-voltage curves for the defect (a, i), the anodically delaminated area...

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