Electrochemical Mechanism of the Preparation of High-Purity Indium by Electrodeposition

Indium is a crucial material and is widely used in high-tech industries, and electrodeposition is an efficient method to recover rare metal resources. In this work, the electrochemical behavior of In3+ was investigated by using different electrochemical methods in electrolytes containing sodium and indium sulfate. Cyclic voltammetry (CV), chronoamperometry (CA), and alternating current impedance (EIS) techniques were used to investigate the reduction reaction of In3+ and the electrocrystallization mechanism of indium in the indium sulfate system. The cyclic voltammetry results showed that the electrodeposition process is irreversible. The average charge transfer coefficient a of In3+ was calculated to be 0.116 from the relationship between the cathodic peak potential and the half-peak potential, and the H+ discharge occurred at a higher negative potential of In3+. The nucleation mechanism of indium electrodeposition was analyzed by chronoamperometry. The mechanism of indium at potential steps of -0.3 to -0.6 V was close to diffusion-controlled instantaneous nucleation with a diffusion coefficient of 7.31 x 10(-9) cm(2) s(-1). The EIS results demonstrated that the reduction process of In3+ is subject to a diffusion-controlled step when pH = 2.5 and the applied potential was -0.5 V. SEM and XRD techniques indicated that the cathodic products deposited on the titanium electrode have excellent cleanliness and purity.

Automated summary

In this study, the electrochemical behavior of indium was investigated using different electrochemical methods. It was found that the electrodeposition process of indium is irreversible. The average charge transfer coefficient of In3+ was determined using cyclic voltammetry. The nucleation mechanism of indium was analyzed using chronoamperometry, and the reduction process of In3+ was studied using alternating current impedance. SEM and XRD techniques confirmed the purity of the cathodic products deposited on the titanium electrode.