Ionic liquid-based electrolytes for CO2 electroreduction and CO2 electroorganic transformation

CO2 is an abundant and renewable C1 feedstock. Electrochemical transformation of CO2 can integrate CO2 fixation with renewable electricity storage, providing an avenue to close the anthropogenic carbon cycle. As a new type of green and chemically tailorable solvent, ionic liquids (ILs) have been proposed as highly promising alternatives for conventional electrolytes in electrochemical CO2 conversion. This review summarizes major advances in the electrochemical transformation of CO2 into value-added carbonic fuels and chemicals in IL-based media in the past several years. Both the direct CO2 electroreduction (CO2ER) and CO2-involved electroorganic transformation (CO2EOT) are discussed, focusing on the effect of electrocatalysts, IL components, reactor configurations and operating conditions on catalytic activity, selectivity and reusability. The reasons for the enhanced CO2 conversion performance by ILs are also discussed, providing guidance for the rational design of novel IL-based electrochemical processes for CO2 conversion. Finally, the critical challenges remaining in this research area and promising directions for future research are proposed.