Abstract

Electrodeposition or electrosynthesis of any material is dependent on the electrochemical window of the electrolyte, the electrode material, the bath temperature, additives, and the electrochemical parameters, to mention the most important pertinent properties. Let us have a look at an undergraduate experiment, which is quite easy to perform even in a high school chemical laboratory, namely copper electroplating. The teacher will use an aqueous solution containing a copper salt, for example, CuSO₄, mixed with an acidic electrolyte to ensure conductivity, usually H₂SO₄; a steel plate to be plated with copper; and a copper plate for a counterelectrode. If a standard AA primary battery with 1.5 V nominal voltage is connected to this simple cell (minus pole = cathode: steel; plus pole = anode: copper plate), one can see with the naked eye the steel plate being slowly covered by a dull, reddish copper layer, and the copper counterelectrode as such being roughened, manifested as either darkening or brightening of the electrode, depending on the exact conditions. The following reactions occur: