Adsorption of organic solvent vapours on pristine and doped few-layer graphene nanoflakes

Heterosubstitution is widely used to control the surface properties of graphene materials. The knowledge of the mechanism of organic solvent vapour sorption on doped graphene materials is necessary for development of air purification technologies, volatile organic compounds sensors, metal-free catalysis and for many other applications. The effect of N, S and Si doping and oxidative functionalization of few-layer graphene nanoflakes on the adsorption of organic solvent vapours was measured. The nanoflakes were also analyzed by TEM, XPS, Raman spectroscopy and low-temperature nitrogen physisorption. Special attention was paid to the dependence of the isosteric heat of adsorption on the surface coverage for various adsorbate-adsorbent pairs, which carry information about the energy inhomogeneity of the surface, the hierarchy of adsorbate-adsorbate, adsorbate-basal plane and adsorbate-functional groups interactions, and the mechanism of adsorption. This dependence for the hexane sorption can be used to detect hydrophilic groups on the surface, and to compare the degree of curvature of graphene layers in different heterosubstituted graphene materials.