I need to find out the oxidation and reduction potential of Copper.
- Oxidation of Cu(0) into Cu(+1) and Cu(+2) and reduction of Cu(+2) into Cu(0) and Cu(+1) are the details that I want to find out, explained by the following reactions as well
Cu+2 ---> Cu0 or Cu+1
Cu0----> Cu+1 or Cu+2
- from the peak current values in cyclic voltammetry is that the same oxidation and reduction potential were expressed ?
Hi
Maybe I am missing something but basically from a CV you get the oxidation peak and the potential value for this peak at the certain temperature, pH is the oxidation potential. The same goes for the reduction. For a reversible species (Eox+Ered)/2= oxidation-reduction potential. If you do it in the standard condition it will be the standard ox-red potential.
First find a Table of standard reduction potentials. For copper , read here:
https://www.webelements.com/copper/compound_properties.html
CV is not a good way to find these potentials.
I agree with Cornel, CV is not a good way to find the standard electrode potentials. Approximately, we can use CV of a reversible system to determine its formal potential (Eo'): Eo' = (Epa + Epc)/2.
Note that the formal potential is not a true standard electrode potential.
Standard potentials (Eo) refer to states that can never be achieved in practice, namely ideal 1.0 M solutions. A very dilute solution can be reasonably assumed to be ideal (activity coefficient = 1). Very solutions less than 10-2 M, we can use Debye-Hückel Theory to calculate activity coefficients. More concentrated than that, and there is no theory available to do the calculation. Empirical coefficients are necessary. One way around this problem is with Formal Potentials.
By definition Ered = - Eox . The redox potential is not a new/clearly/different defined concept.
For an interpreted Cu CV see:
https://www.researchgate.net/publication/267695029_Electrochemical_impedance_spectroscopic_studies_of_the_passive_layer_on_the_surface_of_copper_as_a_function_of_potential
Data Electrochemical impedance spectroscopic studies of the passi...
Hi Yasun,
I agree with the comments above. Generally speaking, you may be able to obtain formal potentials from the CV curves. These are different from the standard potentials because they have contributions from the activity coefficients which you would need to take into account. Once you have those values you may be able to estimate the standard potentials through extrapolation.
If the redox process is reversible and the kinetics of the reaction at the electrode surface are very fast, then it may be able to use the relationships described above. However, and since your problem is a multi-step process, you should be careful in using these relationships which are generally valid for a single-step reversible process. Furthermore, you could glean important information from CV signals by fitting an appropriate model to the curve. As an example of this please see the paper:
http://www.sciencedirect.com/science/article/pii/S0022311516301064
Finally, and despite the significance of CV in recording valuable information, it is not the best experimental technique for obtaining redox potentials. I suggest you look into Open Circuit Potentiometry (OCP) or other available tools that would give you more accurate results.
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