During study the kinetic of composite electrode of diamond, carbon black and PTFE by cyclic voltammetry by using 5mM of K4Fe(CN)6 with 0.5 M H2SO4 as probe the value of cathodic peak was larger than anodic peak. May I know the reason of this phenomenon?
This is fundamental electrochemical considerations on kinetics and mechanisms. Consult any good electrochemistry textbook.
Dear M. Ajeel,
From my experience with diamond experiments , there are more one reason for that: (1) the sector direction can affected by the defect more than other sectors direction for example 100 sector direction embrace more defect than 111 sector direction .So may the cathode put on 111 sector n and the anode on 100 sector direction in this case you will find difference in spectra strengths where defect can affected the strength (it will be lower than the other).
(2) may the surface of the sample is not regular in this case you have to polish the surface and make it flat and I did not with this resone 100%.
Best regard
its depend on scane rate,, decrease of peack is meaning that deacrease of electroactive Fe3+ . it may be because of side reaction or material deposition that decrease charge transfer
what do you mean by larger? what is important is the charge consumed in both peaks. The shape of the beak depend on may variable in your experiment
Make sure you integrate the correct area. More intense you mean larger current? that is kinetics. But the whole area underneath could be the same
It may be because of the difference between the two diffusion coefficients of your Ox/Red species. Thus, the species with the highest diffusivity will diffuse faster into or out of the electrode surface. This will decrease or increase the concentration gradient between the bulk and the electrode surface resulting in the decrease or the increase of electroactive species on the electrode surface.
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