F-doped carbon derived from asphalt by mechanochemical approach: More effective toward selective CO2 capture

Abstract

Porous carbon materials are a preferred choice for CO2 capture and separation owing to unique physical and chemical properties. Here, mechanochemical synthesis of porous carbon (high surface area, up to 1188 m2g−1) and in situ fluorine doping have been accomplished with asphalt as carbon source and Teflon (PTFE) as porogen and fluorine-doped precursors. Ball milling treatment are indispensable for the subsequent carbonization process of asphalt-PTFE mixture. The particle mixing and surface activation in the solid state are promoted by the input of mechanical energy and reaction mixtures are exposed to mechanical force impact. Meanwhile, the micropores and polar functional groups rich in the as-prepared carbon materials both conduce to higher CO2 capture and increase in adsorption energy based on DFT calculation. As evidence, the CO2 uptake capacity reached to 4.1 mmol g−1 for F-C-30# at 273 K, 1 bar. The CO2/N2 selectivity could reach up to 54 under ambient conditions, thereby reflecting a highly competitive CO2-adsorption capacity.