Hi,

I am doing a bit of research into the electrolysis of H2O under different conditions but am having trouble reading some of the cyclic voltammograms (CVs) that I am getting. I've attached a few sample CVs below.

The electrodes are Cu foil as the WE and glassy carbon plate as the CE, with a Ag/AgCl RE. The electrolyte solution is 1 M NaOH, so fairly alkaline. The main two half reactions I'm expecting to see are of course the oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) from water splitting. Considering the pH of the water, I'm expecting the oxidative peak at around 0 V to be the OER (though this is lower than expected) and the peak at -1 V to be HER. However, there are several other peaks that I can't discern what they are, such as the small, consistent reduction peak around -0.5 to -0.6 V, or the shoulder peaks on either side of the HER peak. I've considered that they might be caused by either something from the electrodes or additional reagents in the electrolyte, but nothing I can think of makes sense here.

Any thoughts and suggestions would be greatly appreciated. Thanks in advance!