Fine-tuned ultramicroporous carbon materials via CO 2 activation for molecular sieving of fluorinated propylene and propane

Abstract

Through moderate CO 2 activation, the phenolic resin-derived carbon (PRC-15CO 2 ) was precisely tuned to an optimal pore size, achieving exceptional C 3 F 6 adsorption capacity and complete C 3 F 8 exclusion. Ultramicroporous carbon materials with precisely engineered pore structures offer a promising pathway for the challenging separation of fluorinated gases with similar physicochemical properties, such as C 3 F 6 (fluorinated propylene) and C 3 F 8 (fluorinated propane). In this work, we report the synthesis of CO 2 -activated porous carbon adsorbents derived from a precursory resin and systematically investigate their molecular sieving behavior for C 3 F 6 /C 3 F 8 mixtures. Through controlled thermal pyrolysis and stepwise CO 2 activation, we tailored ultramicropore size distributions to selectively exclude or admit target molecules. Adsorption studies reveal that optimal CO 2 activation yields pore sizes that enable effective separation of C 3 F 6 from C 3 F 8 , achieving efficient molecular sieving due to size exclusion effects. Excessive activation, however, generates larger pores that diminish selectivity due to nonspecific affinity for both gases. The findings highlight the importance of ultramicropore control for energy-efficient separation of fluorinated hydrocarbons and provide insights for designing advanced adsorbents for industrial gas purification.