Nitrogen-doped porous carbons are attracting considerable attention as adsorbents in CO2 uptake area or for supercapacitors. In this work, nitrogen-doped porous carbons with a high surface area are efficiently prepared through a facile approach by using polyvinylpyrrolidone as carbon and nitrogen sources through ZnCl2 activation at 400-700 A degrees C for 4 h under N-2 atmosphere. The obtained nitrogen-doped porous carbons exhibit a narrow microporous structure (0.4-1.0 nm), high specific surface area (up to 1040 m(2) g(-1)) and corresponding N content of up to 6.3 wt%. These findings are ascribed to the unique features of high specific surface area and rich N content. Such nitrogen-doped porous carbons show high CO2 capture of 4.0 mmol g(-1) (0 A degrees C) and 2.5 mmol g(-1) (25 A degrees C), as well as excellent capacitive performance with a specific capacitance of 292 F g(-1) (in 2 M KOH) at a current density of 0.5 A g(-1) and cycling stability. A symmetrical supercapacitor based on NPCs shows high energy density (23.2 W h kg(-1) at 0.5 A g(-1)) and good cycle stability (96.8% capacitance retention after 5000 cycles) in symmetric two-electrode systems.