H₂/CH₄ gas separation by variation in pore geometry of nanoporous graphene

We studied the behavior of H₂ and CH₄ flowing through various pore geometries of nanoporous graphene using molecular dynamics method. Ten different geometries of pore-18, with different eccentricities, were prepared. It was found that the gas permeance and adsorption layer were heavily influenced by the eccentricity of the pores. On further investigation, it was also found that the jaggedness of the pore geometry played a role as well. It was also noted that at specific eccentricities, pore-18 exhibited hydrogen selective behavior, which was found to extend to pore-12, -14, -16, -20, -24, and -30 as well. Furthermore, it was shown that the H₂ permeance of these pores can reach 9 times the value of that of pore-10 (which was previously found to be the only selective pore). Hence, these pores show H₂ selectivity with high H₂ yields. Thus, this study demonstrates the exciting possibility of creating highly efficient H₂ separators by pore geometry variation. Recent experimental studies, which involve an atom-by-atom removal technique to create nanopores, point to the possibility of obtaining these geometries in the lab. (Figure Presented).