Sustainable waste Biomass-Derived porous carbons with superior hierarchical porosity for High-Performance CO2 capture

The increasing levels of carbon dioxide (CO 2 ) emissions driven by industrial activities highlight the urgent need for the development of efficient and sustainable CO 2 capture technologies. Biomass-derived porous carbons have emerged as promising candidates for CO 2 adsorption due to their low cost, high surface area, and adjustable pore structure. In this study, hierarchically porous carbons (HPCs) were synthesized from waste acer truncatum wood through pre-carbonization and subsequent KOH activation. The synthesis conditions, including activation temperature and activating agent concentration, were optimized to precisely tailor the pore architecture. The resulting HPC exhibited excellent CO 2 adsorption capacities of 7.56 mmol·g⁻ 1 at 0 °C and 4.29 mmol·g⁻ 1 at 25 °C under ambient pressure. Notably, ultramicropores (< 0.7 nm) exhibited a dominant role in CO 2 capture at low pressures, while narrow micropores (< 1.0 nm) contributed significantly across a range of low-pressure conditions. The hierarchical pore structure enhanced CO 2 uptake at higher pressures. Furthermore, the material demonstrated exceptional CO 2 /N 2 selectivity, reaching up to 112 at 0.15 bar and 0 °C, along with good cyclic stability, highlighting its potential in post-combustion CO 2 capture. This work provides a sustainable strategy for converting waste biomass into high-value adsorbents, offering a solution that addresses both environmental concerns and economic feasibility.