(Why redox peak currents are increasing with positive peak potential shift). I have checked many papers on surfactant modified electrodes by immobilization. In all those papers redox currents are increasing with negative shift in redox peak potential. I am unable to understand why in my case redox peak currents are increasing with positive shift in peak potential.
Shifting peak potential towards positive (oxidation peak) / negative (reduction peak) side i.e near to Zero potential indicates modified electrode acting as good electrocatalyst. In my opinion you need to consider more regarding the peak potential difference to highlight the significance of the electrode. Lesser the peak potential difference higher the performance of the modified electrode.
I agree with both colleagues. However, the fact you describe may be related to the fact that you move from cathodic to anodic potentials. Then, it seems that any compound is oxidizing on your cathode but if you moves towards more anodic potentials a reduction peak appears, may related to the oxidation one.
Dear prof. Christian Punct, B.N. Chandrashekar, and Jordi Carrillo Abad
Thanks for your suggestions now we are able to find reasons for it. On the way of investigation we are also able to detect TX-100 aggregated ferrocene.
We strongly feel that
TX-100 molecules may diffuse into the carbon paste electrode and expose more number of ferrocene molecules for electron transfer reactions (which may be the reason for enhanced CV peak currents at TX-100 modified ferrocene electrode when compared to ferrocene modified electrode). Additionally, functional groups such as oxygen present in the TX-100, increase wettability of TX-100 modified ferrocene electrodes, which in turn increases surface area accessibility. Therefore, we are proposing that functional groups present in the TX-100 are responsible for the enhanced CV peak currents at TX-100 ferrocene modified electrode.
The peak potential are shifting in positive direction because hydrophobic part of TX-100 tries to hamper ferrocene oxidation.
We explained the detail mechanism with theoretical support in our recent Electrochimica Acta article (10.1016/j.electacta.2017.11.154).
Thank you so much for all your support @ Prof. Christian Punct.
Best Regards
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