Electrochemical behavior of gallium electrodeposition and inhibition of hydrogen evolution reaction in alkaline electrolyte.

The gallium electrowinning process is always accompanied by hydrogen evolution reaction that results in low current efficiency (CE). In this manuscript, cyclic voltammetry and chronoamperometry studies were carried out to investigate the gallium cathode behavior under various conditions and explore the parameter that is beneficial to improve the CE. The CE of the lead and copper cathodes was higher, while gallium deposited on the titanium, SUS316, and SUS304 cathodes was readily separated. Increasing the overpotential and gallium concentration or decreasing the pH within a certain range was all beneficial to improve the CE, while the temperature had no significant effect on the CE. Kinetic studies of gallium electrodeposition were carried out. The gallium electrodeposition process was determined as mixed control and forced convection is expected to further improve the CE. The apparent activation energy and kinetic current from the electrochemical reactions were determined to be 23.335 kJ mol−1 and 47.6 mA, respectively. [ABSTRACT FROM AUTHOR]