A rational design of cellulose-based heteroatom-doped porous carbons: Promising contenders for CO2 adsorption and separation

•N/ N, S-doped microporous carbons derived from inexhaustible precursor ‘cellulose’.•Cell-UK exhibit microporous texture with high pyrrolic nitrogen (58%).•Excellent CO2 adsorption (297 mg/g) was achieved at 273 K.•IAST determines a CO2/N2 selectivity of up to 113 at 273 K. The present work demonstrates a facile synthesis of cellulose-based novel microporous carbons (Cell-X) for environmental remediation by virtue of their application as CO2 adsorbents. The presence of heteroatoms (N, S) in highly porous carbon frameworks (1032 m2/g) endowed Cell-X with efficient CO2 adsorption and separation characteristics. The optimized sample, Cell-UK, exhibit significantly large micropore volume (0.7135 cm3/g), abundance of narrow micropores (