Synthesis of porous carbon derived from poly(vinylidenefluoride) and its adsorption characteristics for CO₂ and CH₄

The preparation of carbon adsorbents through carbonization of polymer precursors is drawing attention in that it can form uniform size of micropores. In this study, several carbon adsorbents were prepared by carbonization of poly (vinylidenefluoride) (PVDF) at between 500 and 900 °C under Ar or CO₂ carrier flow. The prepared samples exhibited pore size distribution between 0.6 and 1.3 nm, and the pore structure was formed differently according to the carbonization conditions. Especially, the CO₂ caused further activation during polymer carbonization, leading to better development of the microporous structure. The formed micropores were found to be uniformly distributed on the adsorbent surface from TEM image, and their structure could be characterized by XPS analysis. The volumetric adsorption measurements revealed that the porous carbon adsorbents had good CO₂ and CH₄ adsorption performances. Moreover, the measured adsorption capacities were highly dependent on the narrow micropore (<0.8 nm) volume. Based on these results, additional porous carbon adsorbents could be prepared to increase narrow micropore volume by varying the sample amount and temperature increasing/decreasing rates. As a results, one of the prepared porous carbon adsorbents showed remarkable adsorption capacity at 25 °C; 5.02 mmol/g for CO₂ and 2.35 mmol/g for CH₄.