Graphene Oxide as an Optimal Candidate Material for Methane Storage

TL;DR

This study demonstrates that graphene oxide significantly improves methane adsorption energy compared to graphene, making it a promising material for natural gas storage in vehicles, based on density functional theory calculations.

Contribution

It reveals that graphene oxide enhances methane binding by 50%, providing insights into the interactions responsible and guiding the design of better storage materials.

Findings

Graphene oxide increases methane adsorption energy by 50%.

Enhanced binding involves dispersion, electrostatic, and geometric effects.

Insights can inform the design of advanced methane storage materials.

Abstract

Methane, the primary constituent of natural gas, binds too weakly to nanostructured carbons to meet the targets set for on-board vehicular storage to be viable. We show, using density functional theory calculations, that replacing graphene by graphene oxide increases the adsorption energy of methane by 50%. This enhancement is sufficient to achieve the optimal binding strength. In order to gain insight into the sources of this increased binding, that could also be used to formulate design principles for novel storage materials, we consider a sequence of model systems, that progressively take us from graphene to graphene oxide. A careful analysis of the various contributions to the weak binding between the methane molecule and the graphene oxide shows that the enhancement has important contributions from London dispersion interactions as well as Debye interactions and higher-order electrostatic interactions, aided by geometric curvature induced primarily by the presence of epoxy groups.