The role of 5,10,15,20-tetraphenylporphyrinatocobalt(II) ([Co(tpp)]) as a catalyst on molecular oxygen (O(2)) reduction by ferrocene (Fc) and its two derivatives, 1,1'-dimethylferrocene (DFc) and decamethylferrocene (DMFc) at a polarized water|1,2-dichloroethane (DCE) interface has been studied. The water|DCE interface essentially acts as a proton pump controlled by the Galvani potential differ...