I am using amperometric i-t curve in electrochemical work station at set potential of -0.6V vs Ag/AgCl wit Ti plate as anode and graphite as working electrode in an undivided cell. Na2SO4 (0.05M), spiked with an organic pollutant at pH 3.0 with continuous aeration and Fe3O4 as catalyst
Everything is fine and then suddenly current start declining after about 30 minutes of start up. I am confused why the current showed a sharp decline. Posted a screen shot for reference. It continue to goes up until i stop it after 60 minutes.
Thanking in anticipation
The system looks complicated. You probably know that if oxygen is reduced at cathode then something should be oxidized at the anode. You need for the beginning to do this process in a divided cell and besides to check resistance of the cell as a whole and of Ti anode.
Seems you are trying to test the stability of your ORR catalyst. If it is, I think it is normal phenomena and current decrease is due to decreasing activity of catalyst. For reference, you can check ORR papers.
Thanks.
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