Electrodeposition of Ga-Sn thin liquid films from a deep eutectic solvent for CO2 reduction

Gallium-based liquid metals are considered as promising catalysts for electrochemical CO 2 reduction due to their ability to effectively prevent the adhesion of byproduct carbon, which leads to the deactivation of electrode materials. In order to increase the specific area of liquid alloys, Ga-Sn thin liquid films were electrodeposited from a deep eutectic solvent composed of acetamide and dimethyl sulfone. Electrodeposition of Ga-Sn thin films with varying compositions that follow normal deposition behavior achieved, resulting in Sn rich in overall composition. To obtain Ga-rich thin liquid films, a straight forward and efficient two-step electrodeposition approach was employed. A layer of Ga thin film was firstly electrodeposited on the substrate, followed by electrodepositing a Sn layer. The prepared Ga-Sn thin films were applied for electrochemical reduction of CO 2 in a CO 2 -saturated 0.1 M KHCO 3 solution. Ga-Sn alloy with 91.6 at% Ga was in the liquid state at 25℃ and showed an excellent performance in reduction CO 2 to formate. The Faradaic efficiency reached 80 % and the partial current density was 46 mA cm −2 .