I am trying to reduce H2O2 at GCE and other modified electrodes using cyclic voltammetry. But I am not getting well defined reduction peak. Can anybody tell what could be the reason?
Why not oxidize the peroxide on platinum? Or use an enzyme with a transition metal mediator? Hydrogen peroxide reduction is not well behaved on carbon, electron transfer rates are too slow. Of course all the conditions matter in electrochemistry...pH solvent, electrolytes, dissolved oxygen, etc. etc.
Yes. And cyclic voltammetry is the worst possible way to quantitate anything! Too many things are changing at once. It is an excellent diagnostic tool for mechanisms and such, but not a way to determine concentrations of a solute... Be well John!!! Pete.
Ohmic resistance (maybe due to diluted buffer?), placement of Ref electrode could be checked. Uncompensated resistance also leads to poor voltammetric waves. Check if there is any improvements at lower scan rates, lower H2O2 concentrations, higher buffer concentrations. Maybe try stationary voltammetry if RDE available. Lastly, make sure your background voltammograms are decent (no peaks) and estimate double layer capacitance from them; it should be within the limits for your material.
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