Design and fabrication of hierarchically porous carbon frameworks with Fe2O3 cubes as hard template for CO2 adsorption

Hierarchically porous carbons have triggered lots of research interests due to their unique structure properties. Herein, we presented the synthesis of hierarchically porous carbon frameworks (HPCFs) with the combination of hard template and chemical activation methods. Well-defined cubical macropores were formed by duplication of the hard template's shape, and developed microporosity in the carbon frames was created by NaOH activation. The HPCFs were also successfully doped with nitrogen using urea. Effects of different synthesis parameters on the carbons' morphology and textural properties were analyzed and discussed. The carbon yield could be considered as an indicator of the structure's integrity. Usually the carbon framework collapsed when a very low yield was observed. The carbons' CO2 adsorption performances were systematically investigated. Effects of nitrogen doping at different pressures were carefully studied. Results from the current and reported works demonstrated that CO2 uptake at 20 bar depended on the carbons' surface area. The fitting results showed that surface area of 100 m(2)/g corresponded to CO2 uptake of 0.82 mmol/g. For CO2 adsorption under different conditions, heteroatom doped porous carbons with high porosity and lots of small micropores are the most desirable.