N-containing porous carbon was facilely synthesized by carbonization of melamine colloidal spheres and further activation with K2CO3. The nonactivated porous carbon exhibits excellent CO2 adsorption selectivity with an ideal adsorbed solution theory (LAST) selectivity factor of 129 (CO2/N-2 = 15:85, 1 bar, 25 degrees C) and great CO2 capture capacity (1.26 mmol/g), at low pressure (0.15 bar, 25 degrees C). Moreover, the performance of the material can be further enhanced after activation by K2CO3 with 3.71 and 6.19 mmol/g CO2 uptake at 25 and 0 degrees C, respectively, under atmospheric pressure. Furthermore, the dynamic breakthrough tests also validate the ability of porous carbon to preferentially adsorb CO2, which can be attributed to the abundant micropores and high N content of the porous carbon, having been proved by detailed experiments and characterization methods. In addition, the porous carbon has great regenerative capacity and proper heat adsorption. Hence, porous carbon can be used as a valuable candidate for a CO2 adsorbent in extensive practical applications.