Differentiate faradaic and non faradaic reaction
Answers
Answer:
Faradaic reaction is a heterogeneous charge-transfer reaction occurring at the surface of an electrode.
Explanation:
Both Faradaic and Nonfaradaic processes can take place at an electrode. The difference between the two processes is clearly discussed in several classical sources, but reference to charge transfer across the metal-solution interface as a defining feature of a Faradaic process, leads to ambiguities. We argue that in a Faradaic electrode process both reactant and product species must be part of a bulk phase which is not the electrode. Then, in a Faradaic process, after applying a constant current, and when the bulk phases have constant composition, the electrode charge, voltage and composition will go to constant values, unchanging in time. Thus, a current-voltage curve, or polarization curve, can be constructed based on data from steady-state experiments. This i−V curve characterizes the Faradaic process. For a Nonfaradaic process, however, charge is progressively stored, and the electrode composition changes in time. To characterize a Nonfaradaic process, we inject a discrete amount of electronic charge in an electrode, equilibrate the system, and record the electrode voltage. Repeating this procedure multiple times, a charge-voltage curve can be constructed based on equilibrium data. For the water desalination method called capacitive deionization (CDI) the difference between Faradaic and Nonfaradaic processes is of special importance because both processes occur in CDI.