Dear Dagninet,

The cause is that at low scan rate the current density response of your electrode is almost the maximum at steady-state condition. For higher scan rates, you got the transient response that is part of the maximum steady-state current. The limiting current is the same for both scan rates, so for higher scan rates it will be high compared to other values.

In addition, it shows you that your electrochemical reaction has a low reaction rate. Then, when you apply low scan rates the reaction has a higher time to occur and, consequently, the peak associated with it grows and vice versa.

I have a more spesific question for you. What is your system and can you define high and low scan rates. Thiswill help me to better understand your system and question

If I understand your question the system I used is three electrodes pt, Ag/AgCl in 3M KCl and polypyrrole composite film as counter electrode, reference electrode and working electrode respectively, in 2M NaCl electrolyte solution. high scan rate means high voltage scan per second and low scan rate is low voltage scan per second. for example, 100mv/s is high scan rate than 20mv/s.

Dear Tomer Noyhouzer

first thanks for your willingness to give answer for my question. next here is the explanation you asked me to clarify it. If I understand your question the system I used is three electrodes pt, Ag/AgCl in 3M KCl and polypyrrole composite film as counter electrode, reference electrode and working electrode respectively, in 2M NaCl electrolyte solution. high scan rate means high voltage scan per second and low scan rate is low voltage scan per second. for example, 100mv/s is high scan rate than 20mv/s.

Could you show me a plot of your system?

Dear Tomer Noyhouzer

Here is below I attached the plot.

It looks like a capacitor voltammogram at lower scan rates. I suggest you to do more experiments at 10 and 1mV/s to determine if the trend is correct.

yes, I will try , thank you very much.

Dear Jordi Carrillo Abad  and Tomer Noyhouzerear

I tried what you suggest me from 1-20 mV/s in this case  broadness increases with scan rate but, after 20mV/s the trend stars reverse. what can you suggest me here? can I do at this scan rates only? can I have a reason?