Synthesis of nitrogen enriched porous carbon sponge with the assistance of hard template and physical activation for highly efficient CO2 adsorption

Porous carbons are attractive materials for CO2 capture due to their unique properties. In the current work, N-doped porous carbon sponge (NDPCS) was synthesized with a combined hard template and CO2 activation method, and the applications in CO2 adsorption were also studied. Correlations between synthesis parameters and the product’s morphology were revealed, and effects of the activation conditions on N content and textural properties were analyzed. CO2 adsorption performances of the NDPCS were also thoroughly investigated. The influences of various physicochemical properties on adsorption properties were discussed. CO2 uptake at 25 °C and 1 bar was relatively low (2.16–2.50 mmol/g). However, NDPCS-3–3 showed impressively high adsorption efficiency of 1.63 (mmol/g)/(100 m2/g), much better than some of the best performing samples from reported works. The superior performances were attributed to the combined effects of abundant ultramicropores and enriched N-doping. The current work showed that the NDPCS had great potential for applications in CO2 capture. [Display omitted] •NDPCS is prepared with a combined hard template and CO2 activation method.•NDPCS perfectly inherits the polyurethane sponge template’s morphology.•N content of the NDPCS reaches a very high level of 8.80–13.98 wt%.•At 25 °C and 1 bar, NDPCS-3–3 has adsorption efficiency of 1.63 (mmol/g)/(100 m2/g).