A ROTATING RING-DISC STUDY OF THE INFLUENCE OF THIOUREA ON THE ELECTRODEPOSITION OF COPPER FROM ACID SULFATE-SOLUTIONS

The effects of thiourea on the mechanism of the Cu/Cu2+ system were st udied using Pt/Pt and Cu/Pt rotating ring disc electrodes in a 0.7 M C uSO4-1.8 M H2SO4 solution. Thiourea at low concentrations inhibits the reduction of the intermediate Cu+ to Cu on a copper surface. Thus mor e Cu+ escapes from the disc into solution and the amount of Cu+ observ ed at the ring grows with thiourea concentration. At high thiourea con centrations, the amount of Cu+ reaching the ring becomes very small be cause of complexation effects.