Theoretical study of strained porous graphene structures and their gas separation properties

The structural deformation of porous graphene (PG) under tensile stress and the diffusion properties of H2, O2 and CO2 through PG under different strain conditions have been investigated using the first-principles density functional theory. It is found that the application of a tensile stress can effectively increase the diffusion rate of H2, O2, and CO2 in PG by up to 7, 13, and 20 orders of magnitude, respectively. Therefore, we propose that applying tensile stress is an effective way to control the diffusion rate of gases through PG. By applying sufficiently large tensile stress, one might able to use PG for filtering larger gas molecules such as O2 in addition to previously proposed H2. The results open up an opportunity to utilize PG as a controllable gas separation membrane, leading to wide range of energy and environmental applications.