By using the cathodic and anodic peak separation, can we comment on electrochemical reversibility?
Hey there,
for a reversible system, you'll have an interpeak distance of 59/n (where n is the stoichiometric number of electrons involved).
If you have a quasi-reversible system (interpeak distance > 59/n), you could try to estimate the standard electrochemical rate constant (k0) by using the Method of Nicholson.
Also, note that:
- If your redox couple is surface-sensitive, the kinetics are influenced by the surface functionalities of the electrode (it is the case for the ferri-ferrocyanide couple for example; IrCl62-/IrCl63- isn't surface-sensitive)
- if your electrode is porous, this may artificially lower your interpeak distance.
Hey there,
for a reversible system, you'll have an interpeak distance of 59/n (where n is the stoichiometric number of electrons involved).
If you have a quasi-reversible system (interpeak distance > 59/n), you could try to estimate the standard electrochemical rate constant (k0) by using the Method of Nicholson.
Also, note that:
- If your redox couple is surface-sensitive, the kinetics are influenced by the surface functionalities of the electrode (it is the case for the ferri-ferrocyanide couple for example; IrCl62-/IrCl63- isn't surface-sensitive)
- if your electrode is porous, this may artificially lower your interpeak distance.
Absolutely yes! In fact the peak separation (for chemically reversible systems) is the quickest judgment of electrochemical reversibility.
A very basic question for a Research Forum... Please read any textbook on electrochemistry.
We can comment on chemical reversibility on seeing the cathodic and anodic current ratio if exact 1 which is different from electrochemical reversibility, however is there any relation to those kind of reversibility with Formal potential which could makes a sense to justify that.
In CV technique is characterized by four parameters
1. Anodic current , 2. anodic potential , 3. cathodic potential and 4, cathodic current
when we add redox species (analyte) to the electrochemical cell contain working electrode, counter electrode and reference electrode in suitable electrolytic solution and these electrodes connected to the potentio meter , there are three types of electrochemical reactions occurred which are
1. reversible reaction, 2. irreversible reaction and 3. quasi reversible reaction, these types of reactions depends on the rate at which electron transfers occur between working electrode and solution redox species ,
If the the reaction is said to reversible reaction the rate of transfer of electron between working electrode and solution redox species is fast, and it is further checked by analyzing CV graph, the difference between anodic potential and cathodic potential is equal to 59/n mV where n is the number electrons involved in the redox reaction or the ratio of anodic current to the cathodic current is 1 or even if you apply different scan rates the the positions of anodic and cathodic currents not shifted either + or - potentials.
If the the reaction is said to Ir reversible reaction the rate of transfer of electron between working electrode and solution redox species is slow, and it is further checked by analyzing CV graph, the difference between anodic potential and cathodic potential is greater than 59/n mV where n is the number electrons involved in the redox reaction or the ratio of anodic current to the cathodic current is not 1 or even if you apply different scan rates the the positions of anodic and cathodic currents shifted either + or - potentials.
if the rate of electron transfer reaction takes place intermediate between reversible and irreversible then it is called quasi reversible reaction, here Nernst equation is not apply.
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