Hello everyone.....
Am currently investigating the supercapacitive performances of a carbon based material in both two and three electrodes configuration. I observed that the potential window are different when recording the cyclic voltammagroms under two and three electrodes set up.While, potential window is only 1 V under three electrode configuration, its increases to 1.2 V under two electrode configuration. Is there any scientifically accepted reason (s) for this observation...?
For a 3 electrodes cell, while recording a CV or CA:
- you may use a common voltmeter to monitor the difference potential (Eaux-Eref ) between AUX and REF
- what you see recorded in a voltammogram is the potential difference (Ework -Eref) between WORK and REF.
For a 2 electrodes cell:
- what you measure is the potential difference (voltage) (Ework - Eaux).
Now you have all data to verify that:
(Ework -Eref) - (Eaux-Eref ) = (Ework - Eaux)
Hello,
I think, there is an error in your text Cornel Radu , in 3 electrodes system, you measure E(work)-E(ref) and in 2 electrodes system you measure E(work)-E(aux). So depending your configuration, you don't measure the same voltage, as you measure the voltage between different electrodes.
You are right Mr. Thomas Perrier! Further, reference electrode luggin tip should be as close to the WE as possible in order to minimize ohmic drop, particularly in case of non-aqueous solutions of high resistance.
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