Influence of the substrate's surface structure on the mechanism and kinetics of the electrochemical UPD formation of a copper monolayer on gold

► Cu UPD was studied onto different gold substrates, Au(1 1 1) and polycrystalline gold. ► Experimental potentiostatic current density transients were recorded in this system. ► j-t plots were analyzed using existing theoretical models. ► Formation of the Cu monolayer follows the same mechanism in both cases. ► Mechanism involves simultaneous presence of Cu adsorption and 2D nucleation.