Nanoporous (styrene-divinylbenzene)-based ion exchange resin-based carbons (MPCs) were prepared by MgO-templating synthesis and activated by KOH. MPCs were prepared from a (styrene-divinylbenzene)-based ion exchange resin by the carbonization of a mixture with Mg gluconate at 900 degrees C. And then, the prepared MPCs were treated with KOH at KOH/MPCs ratios ranging from 0.5 to 4 at 800 degrees C. Low KOH/MPCs ratios (KOH/MPCs ratio = 1) tended to favor the formation of micropores, whereas higher KOH/MPCs (KOH/MPCs ratio = 4) led to the formation of mesopores. The treated MPCs with a KOH/MPCs ratio = 1 exhibited the best CO2 adsorption value of 266 mg g(-1) at 1 bar. However, the treated MPCs with a KOH/MPCs ratio = 3 exhibited the best CO2 adsorption value of 1385 mg g(-1) at 30 bar. This result indicated that the CO2 adsorption capacity of nanoporous carbons attributed to the mesopore volume fraction at higher pressure. Crown Copyright (C) 2012 Published by Elsevier B.V. All rights reserved.