A POTENTIAL-PULSE INTERFERENCE METHOD FOR STUDIES OF THE NUCLEATION OF A SINGLE SILVER CENTER ON CARBON MICROELECTRODES

A potential-pulse interference method has been developed for detailed studies of the nucleation at a single nucleus. Following a potential s tep from a positive overpotential to a sufficiently negative overpoten tial at which nucleation takes place, a single reverse pulse or repeti tive potential-pulse train is then applied at certain stage before a c ritical nucleus is formed to interfere with the nucleation process. Nu cleation is then allowed to continue at a stable overpotential until a critical nucleus is formed. By comparing the arrival-time distributio ns of the critical nuclei with and without the pulse interference, inf ormation about the mechanism of the nucleation can be obtained. In par ticular, it is found that a termination process is involved in the for mation of a single silver nucleus at medium and low potentials, and th at the structures of the critical nuclei may be different at different overpotentials.