On the electrodeposition of arsenic in a choline chloride/ethylene glycol deep eutectic solvent

The electrochemical behavior of arsenic(III) is investigated in the ethaline deep eutectic solvent (DES) that is obtained by mixing 1 mol eq. of choline chloride and 2 mol eq. of ethylene glycol using As₂O₃ as the As(III) source. Cyclic voltammetry and rotating disc voltammetry experiments indicate that the reduction of As(III) to As is a single step three electron transfer process with slow kinetics. Chronoamperometry experiments indicate that the deposition of arsenic at a glassy carbon electrode involves with an overpotential-driven three dimensional instantaneous nucleation/growth process. The calculated number density of the nuclei increases as a function of applied overpotential. Amorphous arsenic coatings are prepared using constant potential, constant current, and pulse potential electrolysis experiments. The morphology of the electrodeposits is examined by SEM.