Cyclic voltammetry on 0.1M KCl

  • I had the rodeostat hooked up with the CH Instrument counter electrode and Ag/AgCl reference electrodes. I made the same carbon paste electrode shown in the blog.

    Next I placed the electrodes in the beaker and ran cyclic voltammetry on 0.1M KCl. 100uA, -1V to 1V, scan rate 0.5 V/s. I obtained a graph that looks like this.
    alt text
    Is this correct?

    Ran two cycles but the voltammetry doesn't overlap
    alt text

  • Hi James,
    A couple of notes.

    • In the ascorbate experiment described here, I used 50 mV/s, whereas you are using 500 mV/s (0.5 V/s)

    • Also, in that experiment I was using ascorbate, so I think you can go ahead and start testing your set-up with ascorbate

    • In my experience, the first CV cycle is different from the rest of the cycles. For example, when I run the experiment with 5 cycles, cycles 2-5 are very similar and overlap, whereas cycle 1 will be slightly offset from these. I usually use the cycles that overlap and discard data from cycle 1

  • Yes. I ran the tests with ascorbate. 0.5V/s seems to work fine, 50mV/s is very slow, took like 5+ min for 5 cycles.

  • Hi James,
    I would recommend running the cyclic voltammetry experiment from 0.1 V to 1.0 V, at 50 mV/s for a few cycles (3-4 should be plenty). That would be a direct comparison to the experiment I described.
    Let me know how that experiment works and we can go from there.

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