Covalent organic framework-based catalysts for efficient CO₂ utilization reactions

Anthropogenic CO₂ emissions threaten the synergy between human society and the natural environment. To mitigate CO₂ emissions, several CO₂ utilization techniques have been proposed. Covalent organic frameworks (COFs), a promising class of porous crystalline materials, have been extensively explored for efficient CO₂ utilization owing to their unique features. In particular, well-designed COFs with diverse active sites provide great opportunities to realize CO₂ conversion. Herein, we review recent progresses in the design, synthesis, and catalytic mechanisms of COF-based functional materials for CO₂ utilization reactions such as photo/electrocatalytic CO₂ reduction, cycloaddition, carboxylation, and hydrogenation. We thoroughly evaluate and discuss photocatalytic CO₂ reduction reactions using pristine and metalated COFs; CO₂ electroreduction and carboxylation reactions using different metal-based COFs; and CO₂ cycloaddition reactions using non-metalated, metalated, and ionic liquid-functionalized COFs. Finally, the challenges and prospects of CO₂ utilization using COF-based catalysts are highlighted.