In an oxidation process by cyclic voltammetry, compared to naked ITO electrode, I got less positive peak when ITO was coated with by solid phase catalyst. Do i interpret the less positive peak as lower activation energy/overpotential is required for the oxidation process with my catalyst?
Hi: There are 3 possible answers.
1. If you had cycled the electrode to the negative end of the cycle, some of the ITO may have been lost ( got reduced) and the effective area might have been reduced. You can check this by repeatedly cycling and watching for a gradual reduction in the cathodic peak height and a corresponding decrease in the anode peak
2. The second possibility is that you are experiencing a slight irreversibility in the redox reaction you are studying. The irreversibility will shift the voltage of the peak and its height as well.
3.It is also possible that the product of reaction is too slow to diffuse out and the products are polarizing the electrode more causing a lowering of the height and shifting of potential.
In order to give a better interpretation of your result, you should scan at different scan speeds in that way you could calculate the transfer constant (Khet) of ITO for the process and the Khet for you catalyst. (This could be accomplished by Bultler-volmer law)
If the shift of the voltage if is on the right direction means more irreversible process if the shift is to the left means less energy. Of course you need to be sure that no desorption process are occurring so you should do a lot of cycles preferentially at low speeds 5 mV/s or 10 mV/s
Good luck
Sorry for insufficient information... but my catalyst has good affinity to oxygen, and i found that during the oxidation process, only when oxygen was presented, the less positive shows. After thousand scans, the oxygen was consumed, the less positive peak disappeared and the original peak (ITO or catalyst in N2) showed again.
Well I think is evident that your process is driven at a lower overpotential due the catalyst after all that's what a catalyst suppose to do. You only need to evaluate the transfer constant of your process with ITO and with the Catalyst I send you some documents that can help in order to improve your analysis
thanks for reminding me that, but I didnt see the less potential peak coming in AuNP/N2 electrode
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