Coupled triple phase boundary processes: Liquid–liquid generator–collector electrodes

Electrochemical processes at liquid–liquid–electrode interfaces involve simultaneous ion transfer and electron transfer. When driven at triple phase boundary electrode systems, electron and ion transfer occur in the same interfacial reaction zone. In this report, preliminary work with a novel electrode system based on two coupled triple phase boundary reaction zones is described. An interdigitated gold band array with 7 µm gold bands separated by 13 µm gaps is employed immersed in aqueous electrolyte with a water-immiscible solution of the redox system N,N-diethyl-N'N'-didodecyl-phenylenediamine (DDPD) in 4-(3-phenylpropyl)-pyridine (PPP) immobilized on the surface. Well-defined generator–collector feedback currents are observed which depend on the volume of deposit, the concentration of the redox system, and the nature of the aqueous electrolyte.