When Carbon Meets CO₂: Functional Carbon Nanostructures for CO₂ Utilization.

Major fossil fuel consumption associated with CO₂ emission and socioeconomic instability has received much concern within the global community regarding the long-term sustainability and security of these commodities. The capture, sequestration, and conversion of CO₂ emissions from flue gas are now becoming familiar worldwide. Nanostructured carbonaceous materials with designed functionality have been extensively used in some key CO₂ exploitation processes and techniques, because of their excellent electrical conductivity, chemical/mechanical stability, adjustable chemical compositions, and abundant active sites. This review focuses on a variety of carbonaceous materials, like graphene, carbon nanotubes, amorphous porous carbons and carbon hybrid composites, which have been demonstrated promising in CO₂ capture/separation and conversion (electrocatalysis and photocatalysis) to produce value-added chemicals and fuels. Along with the discussion and concerning synthesis strategies, characterization and conversion and capture/separation techniques employed, we further elaborate the structure-performance relationships in terms of elucidating active sites, reaction mechanisms and kinetics improvement. Finally, challenges and future perspectives of these carbon-based materials for CO₂ applications using well-structured carbons are remarked in detail.