CO2 reduction on the Li–Ga liquid metal surface

Abstract

Reducing CO₂ emissions is crucial for the future survival of the planet and the demand for innovative technologies to capture and reduce CO₂, focusing on global net-zero carbon emissions is growing significantly. Hence, researchers worldwide are investigating approaches to mitigate the greenhouse effect caused by excessive emissions of CO₂. Low melting point liquid metals offer promising opportunities to exploit novel chemistry in negative emission technologies. In this paper, a high-yield, safe and on-demand approach based on Li-containing liquid metal for the reduction of CO₂ to solid materials at low temperatures and atmospheric pressure is reported. In this process, Li metal plays a major role in driving the dissociation of CO₂ to its elemental constituents, carbon and oxygen. During the CO₂ reduction process, Li dissolved in gallium liquid metal, diffuses to the liquid–gas interface and reduces CO₂ to carbon, while undergoing an oxidation reaction. The resulting crust that forms on the surface of the Li–Ga liquid metal alloy consists of solid carbonaceous materials that can be directly utilized as a supercapacitor, achieving a sustainable process for CO₂ reduction. The use of Li–Ga liquid metal alloys enables CO₂ conversion at near room temperature producing carbonaceous materials that can be effectively integrated into energy storage systems.