Ionic Liquids Functionalized Copper Catalytic Systems for Electrocatalytic Carbon Dioxide Reduction

The extensive combustion of fossil fuels results in excessive release of carbon dioxide (CO2), causing a global environmental crisis. It is imperative to develop sustainable methods for converting CO2 into renewable energy sources. Electrochemical reduction of CO2 (CO2RR) 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 CO2 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 CO2RR catalytic systems. Additionally, it offers suggestions for future research avenues regarding IL-functionalized Cu catalysts. Copper-based catalysts are effective in producing multi-carbon products in carbon dioxide electrocatalysis, but they face issues like hydrogen side reactions, low selectivity, and limited operational range. Modifying copper-based catalysts with ionic liquids can help address these problems. This review provides a comprehensive overview of the structures and mechanisms of ionic liquids in copper-based catalytic systems and suggests future research directions. image