Structure and Chemistry of Graphene Oxide in Liquid Water from First Principles

TL;DR

This study uses first-principles molecular simulations to explore the atomic-scale structure, chemistry, and water interactions of graphene oxide, revealing its clustering behavior, hydrophilicity, and chemical activity in water.

Contribution

It provides the first detailed ab initio analysis of graphene oxide in water, bridging the gap between simple models and experimental complexity.

Findings

Oxygen groups cluster on GO surface

GO exhibits hydrophilicity and fast water dynamics

GO acquires a negative charge in water

Abstract

Graphene oxide is a rising star among 2D materials, yet its interaction with liquid water remains a fundamentally open question: experimental characterization at the atomic scale is difficult, and modelling by classical approaches cannot properly describe chemical reactivity. Here, we bridge the gap between simple computational models and complex experimental systems, by realistic first-principles molecular simulations of graphene oxide (GO) in liquid water. We construct chemically accurate GO models and study their behavior in water, showing that oxygen-bearing functional groups (hydroxyl and epoxides) are preferentially clustered on the graphene oxide layer. We demonstrated the specific properties of GO in water, an unusual combination of both hydrophilicity and fast water dynamics. Finally, we evidence that GO is chemically active in water, acquiring an average negative charge of the order of 10~mC m$^{-2}$. The ab initio modelling highlights the uniqueness of GO structures for applications as innovative membranes for desalination and water purification.