CO2 derived nanoporous carbons for carbon capture

Abstract

Nanoporous carbons (NPCs) were synthesized from CO2 with magnesiothermic reduction for CO2 capture applications. The yield of NPCs was enhanced by a modified magnesiothermic reduction process, in which CO2 instead of Ar was applied to the reactor during heating Mg powders from 500 degrees C to a given reaction temperature (800-900 degrees C). The yields, microstructures, pore structures and CO2 adsorption properties were investigated for a variety of NPCs synthesized under various conditions of reaction temperature and duration (15-60 min). The results show that the synthesized NPCs are mainly mesoporous and composed of well crystalline carbon nanosheets interwoven with amorphous carbon. The yield, BET surface area, total pore volume, narrow microporosity (pore size < 1 nm) and CO2 adsorption capacity were decreased with an increase of reaction temperature and duration. The highest CO2 uptake of 39.7 mg g(-1) at 273 K and 1 bar was obtained in the NPC that was synthesized at 800 degrees C for 15 min and with flowing CO2 during heating at above 500 degrees C. The high CO2 adsorption capacity is resulted from its large surface area and volume of narrow micropores smaller than 1 nm, being of 34.9 m(2) g(-1) and 0.011 cm(3) g(-1), respectively.