Formation of a Copper Oxide Layer as a Key Step in the Metallic Copper Deposition Mechanism

This paper demonstrates the formation of a Cu(OH) 1.5 Cl 0.5 layer as a key step in the metallic copper electrodeposition mechanism in sulfate solutions. This layer is located surprisingly into the metal/solution interface and not on the reaction substrate. The difficult to study metal/solution interface makes indispensable the use of unconventional measurement techniques. In this way, a careful in situ study by means of acoustic impedance techniques associated with gravimetric techniques allowed the growth of this layer during the metallic copper electrodeposition process to be monitored, probably for the first time.