Bottom-up synthesis of graphene films hosting atom-thick molecular-sieving apertures
Luis Francisco Villalobos, Cédric Van Goethem, Kuang‐Jung Hsu, Shaoxian Li, Mina Moradi, Kangning Zhao, Mostapha Dakhchoune, Shiqi Huang, Yueqing Shen, Emad Oveisi, Victor Boureau, Kumar Varoon Agrawal
Abstract
) and is up to two orders of magnitude higher than that of molecular-sieving intrinsic vacancy defects in single-layer graphene (SLG) prepared by chemical vapor deposition. The porous nanocrystalline graphene (PNG) films are synthesized by precipitation of C dissolved in the Ni matrix where the C concentration is regulated by controlled pyrolysis of precursors (polymers and/or sugar). The PNG film is made of few-layered graphene except near the grain edge where the grains taper down to a single layer and eventually terminate into vacancy defects at a node where three or more grains meet. This unique nanostructure is highly attractive for the membranes because the layered domains improve the mechanical robustness of the film while the atom-thick molecular-sized apertures allow the realization of large gas transport. The combination of gas permeance and gas pair selectivity is comparable to that from the nanoporous SLG membranes prepared by state-of-the-art postsynthetic lattice etching. Overall, the method reported here improves the scale-up potential of graphene membranes by cutting down the processing steps.