Hi,
I have been noticed a phenomenon for long that if the ferricyanide solution (in salt buffer) was left open on the bench, the solution would become colorless in hours; but if the solution is degassed and put in the dark anaerobic chamber, the solution will stay its color of ferricyanide for over half month.
This indicates the reduction of ferricyanide to ferrocyanide is somehow facilitated by the light and oxygen. And similar results were also found in some old literature.
My concern is what reaction happens during the process? oxygen could not reduce anything, and the ferricyanide is not (at least not significant) degraded by light, since the color can be recovered if positive potential is applied. So, what is happening? what can be the reducing agent there to reduce ferricyanide?
Thanks.
Cheers, Bin