Hello Priyadharshini Aravind,

Thanks for your reply. Both the electrodes are 99.8% copper

 Hi Christian Punckt,

I am using magnetic stirrer @ 200rpm in a 250ml beaker. Anode and cathode have same area i.e 800mm2 (40mm*20mm). By complex formation what are you referring to?

+1 to Christian's answer.

The voltage behavior is telling you exactly why constant current depositions are problematic (also why 2-electrode experiments are problematic).  Nominally, if you have enough mass transport from convection/flow/stirring, then you can overcome the problem of depletion.  However, even if you do, and all of your cathodic current is from electrodeposition of your desired species, you still have the issue of what is giving [anodic] current at the counter electrode.  Most people don't care and so the fixes are to use (ideally much) larger areas and to use more noble materials as counters (Pt, graphite) that are less likely to end up passivating, filming or contaminating the electrolyte.  

...Looking again at your setup, it could also be as simple as bulk depletion not supporting your current for that length of time, so there may be cathode and anode side reactions.  

Hello Christian,

Thanks for your detailed explanation.

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