My reference electrode is usually standard calomel electrode (SCE) and sometimes NHE. I noticed that with respect to the reference electrode the oxidation value number changes. And my CV look like reversible or quasi reversible or irreversible.
The potential for an Reduction potential E(V) (ex. Fe3+/Fe2+ half-cell is +0.750 V) relative to the standard hydrogen electrode. What is its potential when using a saturated calomel electrode or a saturated silver/silver chloride electrode?
When using a standard hydrogen electrode the potential of the electrochemical cell is
Ecell = EFe3+/Fe2+ − ESHE = 0.750 V − 0.000 V = +0.750 V
When using a saturated calomel electrode
Ecell = EFe3+/Fe2+ −ESCE = 0.750 V − 0.2444 V = +0.506 V
When using a saturated silver/silver chloride electrode
Ecell = EFe3+ / Fe2+ −EAg/AgCl = 0.750 V − 0.197 V = +0.553 V