Synthesis of functionalized 3D microporous carbon foams for selective CO2 capture

Porous carbon materials have been considered as the promising media for post combustion CO2 capture. Development and design of cost-effective carbons with high adsorption capacity and selectivity of CO2 over other gases at low CO2 partial pressures has attracted increasing attention. In this study, a category of functionalized 3D microporous carbon foam was prepared by using inexpensive and commercially available polyisocyanurate foam (PIR) as the precursor via a facile one-step chemical activation process. The porous structure and surface chemistry of the carbon foams can be tailored by adjusting the activation temperature and KOH/PIR mass ratio. At 25 degrees C and a CO2 partial pressure of 0.15 bar, the carbon foam of FC7001 with highest volume of fine micropores (< 0.44 nm) and desirable surface chemistry exhibited exceptionally high CO2 uptake of 2.3 mmol/g whereas FC6001, which had a pure single pore size centered at 0.37 nm, showed highest Henry's law CO2/N-2 selectivity of 200. Furthermore, high CO2 uptake capacity of 19 mmol/g at CO2 pressure of 20 bar and ambient temperature was obtained for the carbon foam prepared at a higher activation temperature and KOH/precursor ratio and with a high surface area of 2207 m(2)/g and micropore volume of 0.876 cm(3)/g. Advanced characterization confirmed that the unique ultra-microporous structure and surface chemistry originated from intercalated potassium in the form of surface extra-framework ions governed the selective CO2 adsorption of the carbon foams at low CO(2 )partial pressures whilst the high micropore volume determined the CO2 adsorption at high CO2 pressure. This work provides a potentially new pathway to recycle polyisocyanurate foams by producing efficient CO2 adsorbents.