Facile synthesis of ultrahigh-surface-area and hierarchically porous carbon for efficient capture and separation of CO₂ and enhanced CH₄ and H₂ storage applications

Ultrahigh surface area and hierarchically microporous carbons functionalized with heteroatoms are critical for many applications, particularly gas storage and separation. However, the facile synthesis of such carbons remains challenging. Herein, we present a single-step activation strategy for producing porous polymer-based ultrahigh surface area carbons through melamine-mediated potassium oxalate activation. As prepared carbon possesses a uniform distribution of heteroatoms and hierarchical micropores, and exhibits a maximum specific surface area of 3463 m²/g, which is among the best reported for carbon materials. The presence of heteroatoms (N and O), along with its ultra-high surface area and hierarchical microporous structure, plays a significant role in storing large amounts of CO₂ (22.8 mmol/g at 298 K/25 bar), CH₄ (10.1 mmol/g at 298 K/25 bar) and H₂ (5.2 wt% at 77 K/50 bar). Furthermore, it demonstrates a selective capture of CO₂ over N₂, CH₄ and H₂. The developed carbon is highly suitable for gas storage and the separation of CO₂ from flue gas and syngas.