Electrocatalytic properties of metal adatoms in a potential range negative to Nernstian bulk deposition

The formation of submonolayers of Cu adatoms on polycrystalline Au in 0.1 M HClO₄ solutions containing only perchlorate anions has been found to proceed at unusually slow rates. This has made it possible to examine the electrocatalytic activity of submonolayer coverages of Cu adatoms exhibiting UPD like properties at potentials more negative than Cu bulk deposition. Rotating ring disk measurements have provided evidence that such layers show electrocatalytic properties for the reduction of nitrate. This process proceeds by a parallel mechanism yielding nitrite as one of the intermediates.