Sustainable Porous Carbon Derived from Lignin for High-Performance CO₂ Capture

The accelerating rise of atmospheric CO₂ remains a central driver of global climate change, highlighting the urgent need for scalable and energy-efficient carbon capture technologies. Porous carbons are among the most promising solid adsorbents due to their high surface area, chemical stability, and tunable pore structures, which facilitate efficient CO₂ adsorption and low regeneration energy. Lignin is a renewable aromatic by-product of the pulp and paper industry, which offers exceptional promise as a sustainable carbon source due to its abundance (50-70 Mt/year), high carbon content (>60 wt%), and rich aromatic structure. Unlike previous reviews broadly covering biomass-derived carbons, this review focuses on recent advances in lignin-derived porous carbons for CO₂ capture, correlating preparation strategies with structural evolution and adsorption performance. Chemical activation, templating, and hybrid methods enable precise control of ultramicropores (<0.7 nm), mesoporous channels, and heteroatom functionalities, which synergistically determine adsorption capacity, selectivity, and regeneration energy. Emerging approaches such as amine functionalization introduce strong chemisorption sites for post-combustion and direct-air capture, while AI-assisted design accelerates understanding of synthesis-property-performance relationships. Despite remarkable progress, remaining challenges in feedstock variability, scalability, and greener process development are discussed along with future prospects for sustainable CO₂ capture using lignin-derived porous carbons.