Shimizu K, Ohba T
Graduate School of Science, Chiba University, 1-33 Yayoi, Inage, Chiba 263-8522, Japan.
Phys Chem Chem Phys. 2017 Jul 19;19(28):18201-18207. doi: 10.1039/c7cp03270f.
Fabrication of a graphene separation sheet is difficult because of the necessity for leakage-free graphene transfer onto a substrate. In this study, porous graphene sheets with thicknesses of one, two, and four layers were directly fabricated on stainless-steel mesh substrates and demonstrated to display high separation ability for H, CO, and CH. The single-layer graphene sample exhibited higher permeance for these molecules than double- and four-layer graphene and displayed similar high selectivity to that of other porous materials. Permeance was proportional to molecular velocity and inversely proportional to interaction strength with graphene; molecular size-dependent permeance was not seen. Molecules that interacted strongly with graphene were attracted to the graphene surface, which hindered permeation. Such graphene surface rejection allowed graphene containing larger pores than the molecular size to provide both high molecular permeance and selectivity. The relationship between the permeance of porous graphene for H and H/CO with selectivity suggested that its permeance was higher than that of other materials with high separation performance. Therefore, the porous graphene samples separated molecules with extremely high permeance by graphene surface rejection.
由于需要将无泄漏的石墨烯转移到基底上，因此制备石墨烯分离片很困难。在本研究中，在不锈钢网基底上直接制备了厚度为一层、两层和四层的多孔石墨烯片，并证明其对H、CO和CH具有高分离能力。单层石墨烯样品对这些分子的渗透率高于双层和四层石墨烯，并且显示出与其他多孔材料相似的高选择性。渗透率与分子速度成正比，与与石墨烯的相互作用强度成反比；未观察到分子尺寸依赖性渗透率。与石墨烯强烈相互作用的分子被吸引到石墨烯表面，这阻碍了渗透。这种石墨烯表面排斥使得含有比分子尺寸更大孔隙的石墨烯能够提供高分子渗透率和选择性。多孔石墨烯对H和H/CO的渗透率与选择性之间的关系表明，其渗透率高于其他具有高分离性能的材料。因此，多孔石墨烯样品通过石墨烯表面排斥以极高的渗透率分离分子。
