Simultaneous and Independent Potentiostatic Control of Two Indicator Electrodes: Application to the Copper(II) /Copper(I) /Copper System in 0.5M KCI at the Rotating Ring-Disc Electrode

Experiments with the ring-disc electrode system usually involve simultaneous and independent measurement of currents through the ring and disc electrode, while holding the potential of one of the electrodes constant and controlling the potential of the other electrode in a prescribed manner. An instrument based upon operational amplifiers is described which provides simultaneous and independent potentiostatic control of the ring and disc electrodes. Its performance was evaluated by studying the copper(II)/copper(I)/copper system in 0.5M KCl. Several new relationships are given for currents observed at the ring electrode in terms of currents at the disc electrode and were verified experimentally using this new instrument.