I am conducting anodic electrodeposition of MnO2 onto a stainless steel substrate, using a platinum strip as a counter electrode. This is done galvanostatically, with the current held between 5 and 10 mA/cm^2 for 10 minutes. The voltage is measured to be around 3-3.5 V. The solution is 0.01M Manganese Acetate in DI water. The experiment is conducted at 60 degrees C. When I begin deposition, a black layer forms on the stainless steel substrate, and bubbles begin forming around the platinum electrode. This corresponds to the formation of MnO2 on the stainless steel, and the splitting of water on the platinum. As time progresses however, the platinum electrode also begins to form this caramel-colored partial coating on it. What is it? Why is it forming? Will it inhibit my deposition? Any help would be greatly appreciated.
Dear Andrew Harkaway ;
The gas bubble formed around the platinum electrode from hydrogen gas evolution release from the substrate, for more details can read;
Article Local Study on Hydrogen and Hydrogen Gas Bubble Formation on...
- https://pubs.acs.org/doi/pdf/10.1021/acs.langmuir.9b00119?src=recsys
- https://link.springer.com/referenceworkentry/10.1007%2F978-3-319-15207-3_14-1
Dear Mahmood H. M.
Thanks for your answer! I agree with you that the bubbles forming is from hydrogen gas evolution. However, I still do not understand where brown layer that is depositing on the platinum is coming from.
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