Nitrogen-rich activated carbon monoliths via ice-templating with high CO2 and H2 adsorption capacities

Hierarchically porous, nitrogen-rich activated carbon monoliths were prepared via ice-templating, carbonization and chemical activation of a polyacrylonitrile (PAN) precursor. Ice-templating of the PAN provided a rigid macroporous polymer scaffold, into which the chemical activating agent KOH was infused, prior to oxidative annealing, carbonization and activation. By varying the amount of KOH infused, the surface areas and N contents of the activated carbons could be varied. This allowed tuning of the materials to favor either CO2 or H-2 uptake - where the optimized material for CO2 adsorption had a BET surface area of 1049 m(2) g(-1), an N content of 14.9 wt%, and a CO2 adsorption of 16.12 mmol g(-1) at 298 K and 10 bar. The optimized material for H-2 uptake had a BET surface area of 2206 m(2) g(-1), an N content of 1.29 wt%, and a H-2 adsorption of 2.66 wt% at 77 K and 1.2 bar. These high CO2 and H-2 adsorption values are achieved despite the relatively facile ice-templating process and the use of the commercially available polymer precursor PAN without further chemical modification.