Redox and electrocatalytic activity of copper in base at unusually low, premonolayer potentials

The assumption involved in this work is that the formation of monolayer (alpha) oxide species, which occurs on copper in base at 60 degrees C at ca. 0.5 V (RHE), is of little relevance to the electrocatalytic behaviour of the metal at low potentials. For many processes occurring at the interface in question the critical potential is ca. -0.1 V (RHE). This is the value where several electrocatalytic oxidation and reduction processes commence or terminate under potential sweep conditions; hydrous oxide films are reduced close to this value and it is possible to produce an active (but transient) state of the metal surface which exhibits a reversible redox response in this region. The results are rationalized in terms of the incipient hydrous oxide/adatom mediator model of electrocatalysis, and the nature of the active site material at the interface is discussed.