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

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 (<0.94 nm) and optimum pyrrolic nitrogen content (58%) which leads to efficient CO₂ adsorption (297.1 mg/g at 273 K and 193.7 mg/g at 298 K/1 bar) and moderately high heat of adsorption (36.70 kJ/mol). Additionally, ideal adsorbed solution theory (IAST) determines a CO₂/N₂ selectivity ~ 110 at 298 K, surpassing the gas separation performance of most reported microporous carbons. Herein, the remarkable CO₂ adsorption and separation performance of prepared materials is attributed to the synergistic role of narrow micropores (<0.94 nm) and surface heterogeneity (N/N, S-doped surfaces). These heteroatoms enriched basic sites induced stronger affinity for acidic CO₂ molecules by generating Lewis acid-base interactions between gas molecules and adsorbent surfaces. Conclusively, present work demonstrates an effort devoted to the rational designing of tunable porous cellulose-based CO₂ adsorbents as promising contenders to mitigate global warming.