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 (al pha) 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 wher e several electrocatalytic oxidation and reduction processes commence or te rminate under potential sweep conditions; hydrous oxide films are reduced c lose 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 th is region. The results are rationalized in terms of the incipient hydrous o xide/adatom mediator model of electrocatalysis, and the nature of the activ e site material at the interface is discussed.