N/S co-doped microporous zeolite-templated carbon for efficient CO2 adsorption and separation

Abstract

Heteroatomic doping of porous carbon materials can give rise to variations in the electronic structure and properties, and has been used to enhance the adsorption and separation of CO2. Herein, N and S doped zeolite-templated carbon (ZTC) are synthesized to study their CO2 adsorption and selective from CO2/N2. ZTC-N, ZTC-S and ZTC-NS exhibit comparatively high CO2 adsorption of 6.12, 7.73 and 9.32 mmol g−1 at 0 °C, which are more than three times than that of ZTC (1.98 mmol g−1). The CO2 adsorption capacity for ZTC-NS at 25 °C and 1 bar can reach as high as 6.03 mmol g−1, which can still occupy approximately 96% after 5 cycles. The obtained carbon materials ZTC-NS with the smallest BET surface area show the highest CO2 adsorption capacity, which indicate an obvious synergistic enhancement effect between sulfur and nitrogen doping. The detailed theoretical calculations indicate N and S co-doping into porous carbon materials assists the change of electrostatic surface potential and local electronic density, thus enhanced the CO2 adsorption.