Synthesis of N-doped hierarchically ordered micro-mesoporous carbons for CO2 adsorption

Abstract

Influences of porous carbon’s physicochemical properties on CO2 adsorption vary with CO2 pressure. The clarification of such complicated influences will undoubtedly be beneficial to the design and synthesis of carbonaceous adsorbents. To this end, in the current work we synthesized a series of N-doped hierarchically ordered micro-mesoporous carbons (NHOMCs). Ordered mesoporous polymer was synthesized with a solvent-free method using F127 as the soft template. After removing F127, the polymer was activated with KHCO3 in the presence of urea at 700–800 °C. The obtained NHOMCs inherited the ordered structure of the polymer, and exhibited high surface area and nitrogen content. Synergistic effects of urea and KHCO3 on nitrogen content and textural properties were discussed and revealed. At 25 °C, high CO2 uptakes of 4.02 mmol/g (1 bar) and 15.42 mmol/g (20 bar) were achieved by the NHOMCs. We then systematically investigated the correlation between CO2 uptake and physicochemical properties. The decisive factors of CO2 uptakes at different pressures (1 bar, 5 bar, 10 bar, 20 bar) were analyzed. We believe the current work will provide helpful insights into the research of porous carbons for CO2 adsorption.