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A series of N-doped porous carbons with different textural properties and N contents was prepared from a mixture of algae and glucose and their capability for the separation of CO 2 /CH 4 , C 2 H 6 /CH 4 , and CO 2 /H 2 binary mixtures under different conditions (bulk pressure, mixture composition, and temperature) were subsequently assessed in great detail. It was observed that the gas (C 2 H 6 , CO 2 , CH 4 , and H 2 ) adsorption capacity at different pressure regions was primarily governed by different adsorbent parameters (N level, narrow micropore volume, and BET specific surface area). More interestingly, it was found that N-doping can selectively enhance the heats of adsorption of C 2 H 6 and CO 2 , while it had a negligible effect on those of CH 4 and H 2 . The adsorption equilibrium selectivities for separating C 2 H 6 /CH 4 , CO 2 /CH 4 , and CO 2 /H 2 gas mixture pairs on the porous carbons were predicted using the ideal adsorbed solution theory (IAST) based on pure-component adsorption isotherms. In particular, sample NAHA-1 exhibited by far the best performance (in terms of gas adsorption capacity and selectivity) reported for porous carbons for the separation of these three binary mixtures. More significantly, NAHA-1 carbon outperforms many of its counterparts ( e.g. MOFs and zeolites), emphasizing the important role of carbonaceous adsorbents in gas purification and separation.