Nitrogen-doped porous carbon nanofiber webs for efficient CO2 capture and conversion

Nitrogen-doped (N-doped) porous carbon nanofiber webs (CNFWs) have been successfully prepared via one-step carbonization-activation treatment of pre-synthesized polypyrrole (PPy) nanofiber webs (NFWs). In this preparation process, the carbonization of the precursor and further activation with KOH were completed simultaneously. We detailedly investigated the effect of different activation conditions on the textural characteristic of final products. The resultant N-doped porous CNFWs were evaluated not only as adsorbents for CO2 capture, but also as catalysts for CO2 conversion, and results indicated that their textural and chemical properties can be tuned by changing the weight ratio of KOH/PPy and activation temperature. Mildly activated CNFWs (KOH/PPy = 2) obtained at 600 °C (CNFWs-600-2) exhibited relatively high CO2 capture capacities of 6.44 and 4.42 mmol g−1 at 0 °C and 25 °C (1 bar), respectively. Furthermore, the CNFWs-600-2 sample was also found to be metal-, solvent-, halogen-free and high-efficiency catalyst towards the cycloaddition of CO2 to epoxides for the synthesis of cyclic carbonates. Our findings may trigger interest in studies of carbon-based materials on CO2 capture and conversion performance.