Ionic Liquids Functionalized Copper Catalytic Systems for Electrocatalytic Carbon Dioxide Reduction

Abstract The extensive combustion of fossil fuels results in excessive release of carbon dioxide (CO 2 ), causing a global environmental crisis. It is imperative to develop sustainable methods for converting CO 2 into renewable energy sources. Electrochemical reduction of CO 2 (CO 2 RR) offers the potential to generate valuable chemicals, including C1 products (e. g., carbon monoxide, methane, etc.) and C2+ products (e. g., ethene, ethanol, acetic acid, propyl alcohol, etc.). Copper‐based (Cu‐based) catalysts show promise for producing value‐added C2+ products, but they face challenges like low selectivity and stability. The catalytic performances of Cu‐based catalysts can be promoted through electronic structure adjustment, selective crystal face exposure, as well as molecular additive approaches. Ionic liquids (ILs), known for their strong CO 2 adsorption capacity, adjustable hydrophobicity, and wide chemical window, hold significant promise for addressing the current challenges associated with Cu‐based catalysts. This review provides a comprehensive overview of the structural characterization and catalytic mechanisms of ILs used in Cu‐based CO 2 RR catalytic systems. Additionally, it offers suggestions for future research avenues regarding IL‐functionalized Cu catalysts.