(First problem)

In this studies, Pt is used as a catalyst to catalyze the oxidation of formaldehyde in this process, CO and formate are formed as reaction intermediate, in this case formate is Oxidized during the reverse cycle(reductive scan)(high potential to low potential) of CV. Is this possible that formate is oxidizing during the reverse cycle of CV and how to explain this reaction?

(ref: Galal, A., Hassan, H., & Atta, N. (2020). Voltammetric study of the electrocatalytic oxidation of formaldehyde on Pt‐Pd co‐catalyst supported on reduced graphene oxide. Electroanalysis. doi:10.1002/elan.202060263 )

(Second problem)

It is known that the forward scan and the reverse scan in cyclic voltammetry are respectively the oxidation peak and the reduction peak, but the principle is because the instrument forces the current to be drawn away from the working electrode during the forward scan (the reverse scan is in contrast). If so, what is the principle of controlling the current?

In my thinking, there should still be the same response under the same potential (because whether the reaction will happen should be controlled by the potential). Why does the forward scan and the reverse scan react differently under the same potential?

Thanks a lot for the answers.