i have performed CV of bare GCE in different concentrations of potassium ferrocyanide with 0.1M KCl supporting electrolyte in milliQ. i have used 1mM 5mM and 10 mM Potassium ferrocyanide will the GCE area change or diffusion coefficient value changed from 7.6*10^-6 as reported in literature.
thanks in advance
Hello! The electroactive area of the glassy carbon electrode can be determined using potassium ferrocyanide (or ferricyanide) using the Cottrell equation or the Randles-Sevcik equation.
In the first case, a chronoamperometry is performed, from a potential E1 where there is no faradaic current to a potential E2 where a limit current is reached for a time = t. I vs t^(-1/2) is graphed and with the slope obtained the area (A) is found.
If you want to use the R-S equation, cyclic voltammetry is performed at different scan rates and I vs v^(1/2) is plotted. From the value of the slope, A is calculated.
In both cases, it is required to know the diffusion coefficient (D) (tabulated in Bard's book), the concentration of the analyte (C) and the number of electrons exchanged in the electrochemical process (n) which in this case is = 1