Experimental and theoretical demonstration of the relative effects of O-doping and N-doping in porous carbons for CO2 capture

Abstract Will the CO 2 capture be affected by the N-doping? This question remains conflict due to the effect of oxygen content in N-doped porous carbons on CO 2 uptake has not been systematically investigated. Herein, the effects of N-free and N-doped porous carbons on CO 2 uptake were investigated by experiments and theoretical calculations. To elucidate the relative influences of nitrogen functional groups, we synthesized a series of carbons without or with N-doping (2.73–9.44% N) by varying the synthesis conditions. Experimental results show that the introduction of oxygen and nitrogen into carbon framework improves CO 2 capture in porous carbons (PCs) and N-doped porous carbons (NPCs). Among these samples, the NPC600 exhibits an exceptionally high CO 2 adsorption capacity (5.01 mmol g −1 at 1 bar and 25 °C). Based on the theoretical calculations, the introduction of nitrogen into carbon framework with high oxygen content further enhances electrostatic interaction for CO 2 adsorption. Moreover, the doping of nitrogen to carbon framework also has a greater effect on both the selectivity for CO 2 /N 2 and the isosteric heat of CO 2 adsorption. It is predicted that this investigation will eliminate any ambiguities and better explain the influence of N-doping on CO 2 capture.