Nanoporous Single‐Layer Graphene Membranes for Gas Separation

Selective Photonic Gasification of Strained Oxygen Clusters on Graphene for Tuning Pore Size in the Å Regime

“…Generally, one always observes a trade-off between gas permeance and gas pair selectivity because the conventional routes for pore incorporation have concomitant pore formation and expansion, which leads to increased pore size at a higher pore density. , However, in the approach we employed, we were able to successfully increase both gas permeance and gas pair selectivity in a systematic way. For the smallest gas that we probed (H 2 ), the increase in gas permeance was significant (a 12-fold increase between 43 and 80 °C).…”

“…These include direct carbon knockout by focused ion beam techniques, , electron beam methods, and plasma procedures, − as well as carbon gasification through chemical etching using KMnO 4 , O 3 , , O 2 , and a combination of these. ,, Oxidation chemistry is extremely attractive for pore formation because of its high uniformity and ease of implementation, which has resulted in the commercialization of oxidized graphene in the form of graphene oxide (GO) and reduced GO (rGO) . However, in order to achieve a fine control over the size distribution in the Å regime of graphene, one must improve the understanding of the underlying mechanism for pore formation …”

“…34 However, in order to achieve a fine control over the size distribution in the Å regime of graphene, one must improve the understanding of the underlying mechanism for pore formation. 35 The following fundamental understandings are crucial: identification of precursors which evolve into vacancy defects or pores; understanding how precursor properties (e.g., chemical composition, structure, and size) are related to that of the pores; and understanding the energetics of the underlying processes (i.e., precursor nucleation and growth and the conversion of precursor to pore). 35,36 Progress has been achieved in some of these aspects.…”

“…35 The following fundamental understandings are crucial: identification of precursors which evolve into vacancy defects or pores; understanding how precursor properties (e.g., chemical composition, structure, and size) are related to that of the pores; and understanding the energetics of the underlying processes (i.e., precursor nucleation and growth and the conversion of precursor to pore). 35,36 Progress has been achieved in some of these aspects. For example, it is now well understood that epoxy groups are generated on the graphitic lattice upon oxidation.…”

“… 34 However, in order to achieve a fine control over the size distribution in the Å regime of graphene, one must improve the understanding of the underlying mechanism for pore formation. 35 …”