On the role of the quadrupole moment of carbon atom on water adsorption on graphite and in graphitic pores

Abstract

Extensive calculations of potential energy between water and finite graphene patches have been made to investigate the effects of the carbon quadrupole moment on the strength of adsorption and the spatial distribution of adsorbed water molecules. It was found that the quadrupole moments of carbon atoms at the edges of the graphene patches are responsible for enhancing the adsorption of water molecules because asymmetry results in greater electrostatic attraction than repulsion, which does not occur at the centres of the graphene patches. The increased electrostatic interactions between a water molecule and the carbon at the edge sites are sufficient to induce clustering and filling of micropores even in the absence of functional groups carrying partial charges.