Density functional theory studies the interaction of neopentane with functionalized porous graphene

Porous graphenes are one of the ideal separation materials. The interaction between neopentane molecule and chemical groups N-, F-, and OH- functionalized single-layer porous graphene model (pore16) was investigated by using first-principles method. The pore size of pore16 modified by one N atom is almost the same (the difference is only 0.006 Å), while the difference of the energy barrier to neopentane is as high as 0.30 eV. For 2Npore16, the energy barrier varies by 0.88 eV, while for 4Npore16, it varies by 0.67 eV. It is evident that as the number of N atoms increases, the energy barrier widens, and this phenomenon is also found in the functionalization of F and OH. The same type and number of functional groups may have different pore sizes, which may result in very different separation properties. Interestingly, adding functionalization leads to the formation of hydrogen bonds in OHpore16, which affects the separation performance of molecule. This implies that not only pore size and shape are the main factors, but also the chemical functionalization of specific sites is the main factor. In general, this study emphasizes an important attraction might be encountered in both the design and modeling of two-dimensional membranes for separating purposes.