Question

Calculate the number of electrons transferred in an idea reversible bioelcetrochemical reaction if the voltage separation between anodic and cathodic peaks is 30 mv in cyclic voltamogram

Answer 1

∆Ep =│Ep anodic - Ep cathodic │= 2.3 RT/nF = 59/n mV at 298K

So basically 59 mV comes from Nernst equation and it is independent of scan rate. If potential difference ( ∆Ep) increases with increase in scan rate, it is characteristics of a slow electron transfer kinetics. Theoretically speaking it is important to get potential difference of 59 mV for a perfectly reversible reaction. However, the calculated value is always higher than 59 mV due to uncompensated solution resistance and non-linear diffusion. The peak separation can be improved by several ways such as cleaning the working electrode, auxiliary electrode must have higher area than working electrode, purging inert gas, distance between working and reference electrode, etc.