Centimeter-scale gas-sieving nanoporous single-layer graphene membrane

High-permeance, molecular-sieving, nanoporous single-layer graphene (NSLG) membranes are highly promising for gas separation. However, the formation of cracks during transfer NSLG to a low-cost porous support is difficult avoid. These detrimental selectivity, and therefore, make scale-up gas-sieving challenging. To mitigate crack on macroporous supports, herein, we demonstrate mechanical reinforcement film with two-layer composite carbon film. The bottom layer 100-nm-thick block-copolymer derived (NPC) pore size 20–30 nm. This makes an intimate contact prevents generation crack. NPC by itself not robust enough cover rough surface supports tends generate occasional cracks. prevented spin-coating 500-nm-thick multi-walled nanotube (MWNT) film, hosting 200–300 nm, top imparts strength NSLG/NPC be successfully suspended low-cost, macroporous, nonwoven metal wire mesh centimeter-scale while completely avoiding As result, H2/CH4 H2/CO2 selectivities 11–23 5–8, respectively, higher than corresponding Knudsen 2.8 4.7, obtained from membranes. reinforced mechanically can withstand transmembrane pressure difference 4 bar. When MWNT directly coated without using intermediate layer, sieving behavior observed, likely due development nanoscale underlines crucial role hierarchical structure in realizing