Structure and stability of graphene nanoribbons in oxygen, carbon dioxide, water, and ammonia

TL;DR

This study uses density functional theory to analyze the stability and structure of graphene nanoribbons in various molecules, predicting their preferred edge configurations in different atmospheres, which aids in synthesis strategies.

Contribution

It provides the first detailed theoretical prediction of GNR edge stability in oxygen, water, ammonia, and carbon dioxide environments, linking chemical conditions to edge structure preferences.

Findings

Oxygen-rich atmospheres favor armchair GNR edges.

Water-saturated environments favor zigzag GNR edges.

Most stable GNR configurations are non-metallic and non-magnetic.

Abstract

We determine, by means of density functional theory, the stability and the structure of graphene nanoribbon (GNR) edges in presence of molecules such as oxygen, water, ammonia, and carbon dioxide. As in the case of hydrogen-terminated nanoribbons, we find that the most stable armchair and zigzag configurations are characterized by a non-metallic/non-magnetic nature, and are compatible with Clar's sextet rules, well known in organic chemistry. In particular, we predict that, at thermodynamic equilibrium, neutral GNRs in oxygen-rich atmosphere should preferentially be along the armchair direction, while water-saturated GNRs should present zigzag edges. Our results promise to be particularly useful to GNRs synthesis, since the most recent and advanced experimental routes are most effective in water and/or ammonia-containing solutions.