Electrodeposition reduction potentials table

There have been numerous applications of controlled-potential coulometry to analysis. Many electrodeposition reactions that are the basis of electrogravimetric determinations can be employed in coulometry as well. However, some electrogravimetric determinations can be used when the electrode reactions occur with less than 100% current efficiency, for example, the plating of tin on a solid electrode. Coulometric determinations can, of course, also be based on electrode reactions in which soluble products or gases are formed (e.g., reduction of Fe(III) to Fe(II), oxidation of 1 to I2, oxidation of N2H4 to N2, reduction of aromatic nitro compounds). Many reviews concerned with controlled-potential coulometric analysis have appeared (1, 20-22) some typical applications are given in Table 11.3.2. 

Because electrodeposition usually is the last procedural step, the composition of the solution can be controlled for ease of electrodeposition. The reagents that are present may consist of an acid to avoid hydrolysis and a redox agent to retain the radionuclide in a state suitable for final reduction. As shown in Table 3.4, metals can be grouped for electrodeposition analysis based on their standard electrode potentials. 

Repetitive square-wave potential techniques switch the potential continuously between the strongly reductive value necessary for the nucleation of the metal particles and a more positive one that is chosen to promote reoxidation of the CP material and thus recuperation of its conducting state, and/or unproved penetration of metal complex anions in the CP layer. Metal complex anions that are used as sources of metal reduction become partially consumed, but also expulsed as doping anions in the course of the reductive dedoping pulse. The size of the electrodeposited metal particles has been found to depend essentially on the frequency of the potential pulses [37,169] (Table 7.3). In fact, the data summarized in Table 7.3 show that by appropriate adjustment of the corresponding parameters, all of the currently exploited electrochemical techniques may result in the deposition of metal NPs in CPs. 

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