Metal-Decorated Crown Ether-Embedded Graphene Nanomeshes for Enhanced Molecular Adsorption

Success in single molecule detection using graphene and graphene oxide has opened up numerous opportunities for other 2D carbon-based substrates to be used for applications in sensing and storage. Graphene nanomeshes, in particular, offer excellent platforms as filtration membranes. Molecular adsorption on pristine graphene is governed by weak van der Waals interactions, while considerable binding strengths can be achieved on defective, metal-doped and metal-decorated graphene. Hypothesizing that crown ether-embedded graphene nanopores can bring in a strong electrostatic component toward molecular binding, electronic structure calculations on the binding of NH3, H2O, and HF on pristine and metal-decorated graphene crown ethers (GCEs), latest addition to the family of graphene nanomeshes are reported. Li+ and Ca2+ decoration on crown-4 and crown-6 GCEs is shown to yield enhanced molecular binding strengths when compared to pristine GCEs and pristine graphene. The per molecular adsorption strengths are found to exhibit a gradual decrease upon addition of molecules. However, the propensity of the molecules to form strong hydrogen-bonded clusters as well as exhibit favorable interactions with the GCEs contributes to a negligible decrease in the per molecular adsorption strengths in some cases. The findings indicate that metal-decorated O-based GCEs are potential substrates for molecular adsorption.