Porous Carbon-Based Adsorbents for CO2 Sequestration from Flue Gases: Tuning Porosity, Surface Chemistry, and Metal Impregnation for Sustainable Capture

Escalating atmospheric CO2 levels and the consequent climate crisis have become urgent imperatives for advancing efficient carbon capture technologies. Porous carbon adsorbents stand out as a leading candidate in this field, owing to their inherently high specific surface areas, tailorable pore architectures, and cost advantages over conventional solid adsorbents. This review focuses on recent progress in the rational engineering of porous carbons for boosted CO2 capture performance, with a particular emphasis on three complementary modification pathways: pore structure refinement, surface functional group regulation, and metal oxide incorporation. We begin by clarifying the distinct mechanisms of CO2 physisorption and chemisorption on carbonaceous surfaces, while also elucidating how key operating parameters (temperature, pressure) and real-world flue gas components (e.g., water vapor, SO2) modulate adsorption behavior. Critical evaluation is then given to strategies for enhancing three core performance metrics—CO2 uptake capacity, selectivity over N2, and cyclic stability—including the construction of sub-nanometer micropores (