Tetrahedral node diamondyne frameworks for CO2 adsorption and separation

The recently reported diamondyne is a fascinating new carbon allotrope with multifunctional applications (J. Mater. Chem. A, 2013, 1, 3851; ibid 2013, 1, 9433). Here we theoretically predict two new tetrahedral node diamondyne (TND) frameworks by replacing the carbon nodes of diamondyne and diamond with the acetylenic linkage (C-C C-C)-formed tetrahedron node. The two resulting theoretical materials (marked as TND-1 and TND-2) exhibit extremely high specific surface areas (SSA) of 6250 and 2992 m(2) g(-1), respectively. Interestingly, the SSA of TND-1 is calculated to be the highest among all porous carbon materials. By further studying the CO2 capture performance of TND-1 and TND-2, it is found that the CO2 uptake of TND-1 reaches 2461 mg g(-1) at 298 K and 50 bar, which outperforms all MOFs, COFs and ZIFs, while the selectivity of TND-2 for CO2/H-2 reaches 104 at 35 bar, which is superior to most of the porous materials. In short, the hypothetical TND frameworks are promising candidates for CO2 capture in practical industry.