Dear Chhetri

If I got you details right then on the cathode you should have this reactions

O2 + 4H+ + 4e- -> H2O E=1.229 V

O2 + 2H+ + 2e- -> H2O2 E=0.70 V

H2O2 + 2H+ + 2e- -> 2H2O E=1.76 V

depending on the potential you are working since it seems you are in a acidic media.

Then in the counter electrode you should have the oxidation. One posible can be 2H2O → O2 + 4H+ + 4e−

but the species can depend on the pH you have or if you have other species.

Hope this helps!

regards

To answer that I need to need what is in the solution. But normally if you are reducing a negative specie at the cathode you will oxidize a positive one at the anode.

my electrolyte solution is 0.1 M HClO4 saturated with O2. i am using 3 electrode cell with Ag/AgCl as the RE , Pt as the counter electrode and synthetically designed electrocatalyst as working electrode for oxygen reduction.

madam since i am a biginner in this field i wanted to have a a prerequisite of the start ups for oxygen reduction.

i would appreciate even a small help to the same.

Probably hydrogen evolution will occur at the CE, as far I understood from your details.

Dear Chhetri

If I got you details right then on the cathode you should have this reactions

O2 + 4H+ + 4e- -> H2O E=1.229 V

O2 + 2H+ + 2e- -> H2O2 E=0.70 V

H2O2 + 2H+ + 2e- -> 2H2O E=1.76 V

depending on the potential you are working since it seems you are in a acidic media.

Then in the counter electrode you should have the oxidation. One posible can be 2H2O → O2 + 4H+ + 4e−

but the species can depend on the pH you have or if you have other species.

Hope this helps!

regards

in cyclic voltammetry you are interested in what occurs at the working electrode. This is the reason why your counter electrode must be many times the area of the working electrode, i.e., to minimize the posibility of reactions that might introduce unwanted species to your system by lowering the current density.

thank you very much Maria, M. Videa and Eswaran. your answers combined with literature survey has helped alot.

It is important to understand that during electrochemical reaction the anodic reaction supply the electrons which are used for reduction in the cathodic reaction. So in H2/O2 fuel cell electrons are produced at the anode due to hydrogen oxidation

H2 -------- 2H(+) + 2 ELECTRONS

These two electrons are used in the reduction of oxygen at the cathode. In cyclic Voltammetry there is no anode because the electrons comes from the battery of the potentiostat which are used for oxygen reduction at the working electrode