Interaction of water with nitrogen-doped graphene

TL;DR

This study investigates how different nitrogen configurations in doped graphene influence water adsorption and orientation, highlighting the importance of local nitrogen chemistry in water-graphene interactions.

Contribution

It provides detailed insights into how graphitic and pyridinic nitrogen configurations affect water adsorption and orientation on doped graphene surfaces.

Findings

Water prefers oxygen-down orientation on graphitic nitrogen

Water prefers hydrogen-down orientation on pyridinic nitrogen

Dispersion forces are key to water adsorption on nitrogen-doped graphene

Abstract

We have studied the interaction of water and graphene doped with nitrogen in different configurations, namely, graphitic and pyridinic nitrogen, by means of the van der Waals density functional. We found that the local nitrogen configuration plays a key role in determining the stable water configuration, while the dispersion force is responsible for the water adsorption. With the graphitic nitrogen, water prefers to orient with its oxygen toward the surface, whereas for the pyridinic nitrogen it prefers to orient with its hydrogens toward the surface, because nitrogen is positively and negatively charged for the former and the latter, respectively. Our results have great implications for the modeling of the interface between water and nitrogen-doped graphitic systems.