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

Abstract

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.