Dear Fatemeh,

thank you for asking this interesting technical question. Clearly, in order to avoid formation of Cu2O during your experiment you need to work in acidic solution. In this context please have a look at the following potentially useful link. It is stated here that the optimum pH for copper electroplating is 3.8 - 4.2:

Improving the Electroplating Process using pH Control

https://sensorex.com/blog/2017/06/13/improving-electroplating-process-using-ph-control/

I hope this helps. Good luck with your work and best wishes, Frank Edelmann

Hi Dr Fatemeh Besharati . The best pH range is 3.8 to 4.2 and difficulties occur at pH above 5.

See the link: https://www.google.com/amp/s/sensorex.com/blog/2017/06/13/improving-electroplating-process-using-ph-control/amp/

See this article http://www.brightmetallics.com/blog/ph-control-to-improve-the-electroplating-process/

Dear Frank T. Edelmann the question is electroless no electroplating