Rakesh Deka to do it by cyclic voltammetry you must use a reversible redox system such as ferricyanide/ferrocyanide. For this, prepare a solution of potassium ferrocyanide 0.01 mol/L in KNO3 1 mol/L. Record cyclic voltammograms at different scan rates e.g. from 10 to 120 mV/s starting with the anodic direction, 5 or 6 scan rates are sufficient. You will obtain voltammograms whose peak current should increase with the scan rate and the peak potentials will also shift with increasing scan rate. With the peak current, construct a graph of Ip vs. square root of scan rate. The slope of the regression line corresponds to the slope of the Randles-Sevcik equation. The area is calculated as: A = m/((2.69*10^5)*(n^3/2)*(D^1/2)*c), where m is the slope of Ip vs. square root of the scan rate, n is the number of electrons transferred (n = 1), D is the diffusion coefficient (cm2/s) and c is the ferrocyanide concentration (10^-5 mol/cm3). Peak current and scan rate should be expressed in A and V/s, respectively.

The experiment can also be done with potassium ferricyanide, where the procedure is the same but the cyclic voltammograms start in the reductive direction. As you can see, to apply this method you must know the diffusion coefficient of the ferrocyanide or ferricyanide species, this can be determined experimentally, or you can assume the value reported at 25°C and perform the experiment under strict temperature control, obviously this option is less accurate but it is widely used.

There is another way to determine the electroactive area and that is by capacitive current from voltammograms of the electrolytic medium against different scan rates, but the former way is the most used.

Regards!

This is the way to meausre "ECSA".

1. we measure "EDL" value of each catalyst by CV measurement under non-faradaic region (+- 0.05 V from OCP of your electrode) depending on scan rate (ex. 10 30 60 100 200 400 mV/s)

2. calculate the slope of current/scan rate graph

-> this is EDL value. if you just want to compare surface area for same electrode with and without your co-catalyst. EDL value is enough (ex. comparison btw Ni foam and co-catalyst modified Ni foam)

However, if you want to compare different type of electrode, you have to calculate ECSA value

3. we can divide every EDL value by specific capacitance of each catalyst for obtaining "ECSA" value.

Only "ECSA" value divided by specific capacitance could be utilized for different types of catalysts.

If you need further information, please check below paper. This paper also include the way to calculate surface area by EIS.

J. Am. Chem. Soc. 2013, 135, 45, 16977–16987

Thanks

Thank you @Javier Ernesto Vilaso Cadre and @Sanghyun Bae for your kind suggestions.

You need to carefully define the relevant surface area in order to get the right answer for your application. Different methods have a different length scale. Methods which rely on diffusion limited current can only resolve to sqrt(2Dt) in dynamic methods, so in a 10 s CV experiment, the spatial resolution will be order 10^-5 m, or 10 um. Surface modifications smaller than this, such as nanoparticles, will therefore not be detected, unless the modification causes the electrode to behave like a thin layer cell. Capacitance methods resolve to the Debye length, ionic strength dependent, where as using metal oxide reduction or beta-hydride peaks for Pt will be on the length scale of the unit cell.

There are IUPAC recommendations which really ought to be more widely read, published in this excellent paper:

Pure Appl. Chem., 1991, Vol. 63, No. 5, pp. 711-734