Facile synthesis of oxidized activated carbons for high-selectivity and low-enthalpy CO2 capture from flue gasElectronic supplementary information (ESI) available. See DOI: 10.1039/c8nj00109j

The prospect of a worsening climatic situation prompts us to develop energy-saving and cost-effective CO 2 capture technologies. In this work, three oxidized activated carbons (ACO- n , n is 1-3) were prepared through a facile synthesis approach via oxidation in the presence of KMnO 4 and concentrated H 2 SO 4 for 0.5, 1.0 or 2.0 hours. Interestingly, these carbon materials ACO- n can exhibit high CO 2 capacity with low adsorption enthalpy and the selectivity toward flue gas can be adjusted by altering the period of oxidation. Among the pristine activated carbon and ACO- n materials, ACO-2 can exhibit the highest CO 2 capacity of 3.01 mmol g −1 under ambient conditions with an adsorption enthalpy of only 23.1 kJ mol −1 , slightly larger than the CO 2 vaporization enthalpy. Its selectivity of 48.5 is double the value of the pristine activated carbon. A column breakthrough experiment was conducted to evaluate the CO 2 separation capability on ACO-2 toward a CO 2 /N 2 (15 : 85 v/v) mixture under kinetic flow conditions, which suggests that the oxidized activated carbon made from sustainable sources is promising for CO 2 capture. The oxidized activated carbon obtained using a facile synthetic approach shows high-capacity and low-enthalpy CO 2 capture with a selectivity of 48.5 toward flue gas, which is double that of the pristine activated carbon.