Ultra-high surface area and nitrogen-rich porous carbons prepared by a low-temperature activation method with superior gas selective adsorption and outstanding supercapacitance performance

Abstract

Ultra-high surface area and nitrogen-rich porous carbons are prepared via a low-temperature and one-pot N-doping method. The obtained carbons exhibited large surface area of 2965.7 m2 g−1 and high N-doping level of 6.6 at%, endowing them as efficient gas-mixture selective adsorbents and excellent supercapacitor electrodes. By optimizing the ratio of porogen/carbon or activation temperature, the as-prepared N-rich microporous carbons possessed outstanding mixed-gas selectivities of CO2/N2 (77.9), CO2/CH4 (12.8), and CH4/N2 (4.9) at 298 K and 1 bar. Furthermore, three samples with almost identical surface properties were successfully prepared by judicious selection of activation conditions, thus the favorable effect of pyrrole/pyridine (N-5) species on gas-mixture separation could be clearly demonstrated. Moreover, as supercapacitor electrodes, the N-doped materials displayed extremely high supercapacitance of 350.2 F g−1 at a current density of 0.5 A g−1 in a 6 M KOH electrolyte solution with superior rate retention of 74.2% at 10 A g−1 and 98% capacitance retention after 8000 cycles.