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

[Display omitted] •A facile activation of porous polymer led to high surface area activated carbon.•Developed carbon possesses hierarchical micropores and uniformly distributed heteroatoms.•The textural properties of activated carbons led to the high gas uptake capacity.•The observed SSABET and gas uptake are comparable to best-reported activated carbons. 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.