Molecular Valves for Controlling Gas Phase Transport Made from Discrete Angstrom-Sized Pores in Graphene

TL;DR

This paper demonstrates the use of gold clusters on graphene to control gas flow through angstrom-sized pores, enabling precise regulation of molecular transport for applications like nanoscale synthesis and sensing.

Contribution

It introduces a novel method to actively control gas flux through individual nanopores in graphene using migrating gold clusters, a significant advancement over previous passive barrier materials.

Findings

Gas flux can be detected and controlled at the single-pore level.

Gold clusters partially block pores and modulate gas permeance.

Permeance switching is attributed to molecular rearrangements in the pore.

Abstract

An ability to precisely regulate the quantity and location of molecular flux is of value in applications such as nanoscale 3D printing, catalysis, and sensor design. Barrier materials containing pores with molecular dimensions have previously been used to manipulate molecular compositions in the gas phase, but have so far been unable to offer controlled gas transport through individual pores. Here, we show that gas flux through discrete angstrom-sized pores in monolayer graphene can be detected and then controlled using nanometer-sized gold clusters, which are formed on the surface of the graphene and can migrate and partially block a pore. In samples without gold clusters, we observe stochastic switching of the magnitude of the gas permeance, which we attribute to molecular rearrangements of the pore. Our molecular valves could be used, for example, to develop unique approaches to molecular synthesis that are based on the controllable switching of a molecular gas flux, reminiscent of ion channels in biological cell membranes and solid state nanopores.