Piran Ravichandran Kidambi1 Sui Zhang2 Qu Chen3 Jing Kong2 Jamie Warner3 Rohit Karnik2

1, Vanderbilt University, Nashville, Tennessee, United States
2, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States
3, University of Oxford, Oxford, , United Kingdom

Direct, bottom-up synthesis of graphene with well-defined pores over large areas can transform the fabrication of nanoporous atomically thin membranes (NATMs) and greatly enhance their potential for practical applications. However, scalable bottom-up synthesis of continuous sheets of nanoporous graphene that maintain integrity over large areas has not been demonstrated. Here, we show that a simple change of parameters during chemical vapor deposition (CVD) on Cu induces in-situ formation of nanoscale defects (≤ 2-3 nm) in the graphene lattice, enabling direct and scalable synthesis of nanoporous monolayer graphene. By solution-casting of hierarchically porous polyether sulfone (PES) supports on the as-grown nanoporous CVD graphene, we demonstrate large-area (> 5 cm2) nanoporous atomically thin membranes (NATMs) for dialysis. The synthesized NATMs show size-selective diffusive transport and effective separation of small molecules and salts from a model protein, with ~2-100× increase in permeance along with better/comparable selectivity to state-of-the-art commercially available polymeric dialysis membranes. Our membranes constitute the largest fully functional NATMs reported to date, which can be easily scaled up to large sizes permitted by CVD synthesis. Our approach highlights synergistic benefits in blending traditional membrane casting with bottom-up pore creation during graphene CVD for advancing NATMs towards practical applications.

Kidambi et al Advanced Materials 2017
Kidambi et al Nanoscale 2017
Kidambi et al Advanced Materials 2017
Wang et al Nature Nanotechnology 2017