CO₂ /N₂ Separation on Highly Selective Carbon Nanofibers Investigated by Dynamic Gas Adsorption

The development of highly selective adsorbents for CO₂ is a key part to advance separation by adsorption as a viable technique for CO₂ capture. In this work, polyacrylonitrile (PAN) based carbon nanofibers (CNFs) were investigated for their CO₂ separation capabilities using dynamic gas adsorption. The CNFs were prepared by electrospinning and subsequent carbonization at various temperatures ranging from 600 to 1000 °C. A thorough investigation of the CO₂ /N₂ selectivity resulted in measured values of 53-106 at 1 bar and 25 °C on CNFs carbonized at 600, 700, or 800 °C. Moreover, the selectivity increased with lower measurement temperatures and lower CO₂ partial pressures, reaching values up to 194. Further analysis revealed high long-term stability with no degradation over 300 cycles and fast adsorption kinetics for CNFs carbonized at 600 or 700 °C. These excellent properties make PAN-based CNFs carbonized at 600 or 700 °C promising candidates for the capture of CO₂ .