Some Unique Aspects of Electrochemical Processes at the Group Ib Metal/Aqueous Solution Interface

Abstract

It has been known for some time that the group Ib metals, copper, silver, and gold, are unique with regard to the magnitude of the surface‐enhanced Raman spectroscopy response recorded, especially for organic bases, at the metal/solution interface. Another unique feature of these three metal electrode systems is described here; they display an adatom (M*)/hydrous oxide transition in which the cation is in the univalent (M+) state. It is suggested that these are the only metals known to date that readily yield relatively insoluble, surface‐bound, univalent hydrous oxide species that behave as strong bases. The redox transition in question, M*/M(1) hydrous oxide, displays an unusual shift in potential upon altering the solution pH; this shift (previously reported for gold and silver) was monitored in the present work by recording the change in onset (anodic sweep)/termination (cathodic sweep) potential for dimethylamine borane oxidation, a reaction induced by the oxidized form of the couple acting as a mediator. It was pointed out that the two unique features of these three metals have the same basis, i.e., an array of univalent cations attached to the electrode surface.