Thin Layer Cyclic Voltammetric Study on the Ion-induced Electron Transfer at the Interface of Nitrobenzene and Water

The reverse electron transfer reaction between tetracyano dimethylbenzoquinone (TCNQ) in the organic phase and K4Fe(CN)6 in the water phase with TBA+ as the common ion in the 2 phases was studied by thin layer cyclic voltammetry (TLCV). Pyrolytic graphite electrode ( 0.64 cm) was used as working electrode with a thin layer of nitrobenzene solution (2 μL) spread upon the electrode as the organic phase. Platinum wire (0.5 mm) and Ag/AgCl electrode were used as the counter electrode and reference electrode respectively, which were placed in the water phase having its total volume of 2 mL. Reverse electron transfer reaction between the oxidized TCNQ+ ion and ［Fe(CN)6］4- ion induced by the common ion TBA+ was observed at the C6H5NO2/H2O interface. It was proved that under definite conditions, by varying the concentration of the common ion in the 2 phases, happening of some impossible electron transfer reaction at the O/W interface was realized, and that such reactions were controlled by the interfacial potential difference. At a constant concentration ratio of the common ion in the two phases, the apparent reaction rate constant (k) was found to be 0.135 cm·s-1·mol-1.