A potential-pulse interference method for studies of the nucleation of a single silver centre on carbon microelectrodes

Abstract

A potential-pulse interference method has been developed for detailed studies of the nucleation at a single nucleus. Following a potential step from a positive overpotential to a sufficiently negative overpotential at which nucleation takes place, a single reverse pulse or repetitive potential-pulse train is then applied at certain stage before a critical nucleus is formed to interfere with the nucleation process. Nucleation is then allowed to continue at a stable overpotential until a critical nucleus is formed. By comparing the arrival-time distributions of the critical nuclei with and without the pulse interference, information about the mechanism of the nucleation can be obtained. In particular, it is found that a termination process is involved in the formation of a single silver nucleus at medium and low potentials, and that the structures of the critical nuclei may be different at different overpotentials.