Electrodeposition of indium from a deep eutectic solvent

In this work the suitability of 1:2 choline chloride/urea deep eutectic solvent (DES) for the electrodeposition of indium has been studied. During deposition, temperature was kept constant at 80°C in favor of mass transfer rate and to lower the viscosity of the solution as well. Voltammetric experiments showed typical overpotential governed nucleation of indium. It was also found with chronoamperometry that electrodeposition of indium at molybdenum electrode proceeds via instantaneous nucleation with diffusion controlled growth, while at gold electrode the deposition proceeds via progressive nucleation with diffusion-controlled growth. EDX analysis and XRD patterns revealed that the deposits were pure crystalline indium for all the cases. The deposits exhibited polygonal shaped grains at low current density and nodular morphology with rounded grains at higher current density.