I am studying the electrochemical behaviour of an organic compound, using cyclic voltammetry at glassy carbon in acetonitrile as a solvent, which undergoes two subsequence reduction processes.
When I increase the scan rate, the two peaks shift towards a negative potential and eventually they overlapped at the highest scan rate (please see the attached picture).
Please, anyone has an interpretation of this case??
First, the displacement for more negative values of potential with the increase of scan rate means that the reduction reactions are irreversible processes. (According to Greef in Instrumental methods in electrochemistry)
Second, you should verify if one reduction peak is dependent of other one closing the potential window for each one. If not, the molecule reduction is believe to occur in different atoms/regions.
I'm not sure about it but probably your molecule has two reduction regions, and the mechanisms can be differents: or adsorption or diffusion controlled processes. They have different correlations when increasing scan rate value. So, maybe one peak increases more than other.
Instead, you can try to use less concentrated supporting electrolyte (if possible), sometimes you get better peak shapes.
Hope I could help you!
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