EVIDENCE FOR ADSORPTION OF FE(CN)63-/4- ON GOLD USING THE INDIRECT LASER-INDUCED TEMPERATURE-JUMP METHOD

The addition of K3Fe(CN)6 and K4Fe(CN)6 to a 1 M KF solution is shown to effect a significant change in the response of the open-circuit potential to a rapid change in the interfacial temperature. Using the indirect laser-induced temperature-jump (ILIT) method the interfacial temperature can be changed in a few nanoseconds-fast enough so that electron transfer between the electrode and Fe(CN)63-/4- (adsorbed or in the bulk) does not have time to occur. The only explanation for a change in the ILIT response is that the Fe(CN)63-/4- adsorbs on the gold surface and effects a change in the structure, and therefore the thermal response, of the double layer.