I am getting an electron count of 2.7-3 for Pt/C ( 20 Wt% ) instead of 4. Can anyone please help me with this problem?
Also, which potential region has to be used for the electorn count- Mixed or diffusion region?
Here, I attached the LSV at different rpm for Pt/C
First of all, in the figure, I think you meant to say NHE and not RHE (unless you did constructed this reference). These two do not always have the same potential. Anyway, maybe you could check the constants. Diffusion coefficient, the concentration of dissolved O2, and kinematic viscosity tend to vary with solution condition (pH, ionic strength, temperature, etc). Also, maybe you can calibrate the electrode surface area by running CV in a Ru(NH4)6 solution.
To add the comments from the Dr. Shimizu, the diffusion coefficient of O2 is different from the pH of the electrolyte. Please find the relevant reference that well-matched with your experiments.
Hi,
I took the all the constants from the reported literature. I have a confusion regarding whether the current has to be normalised with respect to ECSA value or area of electodes?
I think, the current density (j) of your LSV is little lower than the theoretical value (~-5 mA/cm2 at 1600 rpm at 20 mV/s). Thus, if you use this j into your calculation you will always have this n value as you mentioned earlier (you did not mention what equation you used for n calculation).
Therefore, I think, you need to confirm the O2 saturation into the electrolyte for improving j. In present case, however, you can try calculation with the slope of K-L plot as mentioned Mr. Garsany.
Thanks.
Sir,
I used the slope of K-L plot for the calculation of number of electrons. However, the scan rate for the measurement that I used is 5 mV/s (and not 20 mV/s). I think that may be the reason for low current density.
Thank You Sir for the references. I am using 0.1 M KOH as electrolyte.
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