Grand canonical Monte Carlo simulations of nitrogen adsorption on graphene materials with varying layer number

Fabrication of monolayer graphene is a challenge and many processes yield few-layer or multi-layer graphene materials instead. The layer number is an important property of those materials and a quality control variable in graphene manufacture. We demonstrated that N2 adsorption on graphene materials was used to distinguish its layer number. We performed grand canonical Monte Carlo simulation of N2 adsorption on graphene materials with 1-10 layers to indicate the possibility of distinction of layer number by evaluating the dependence of N2 adsorption characteristics on the layer number of graphene materials as well as the adsorption mechanism. The threshold relative pressures of monolayer adsorption of N2 on monolayer and two-layer graphene were 1 × 10−3 and 2 × 10−4, respectively, while those of the others were 1 × 10−4. In contrast, the threshold pressures of second layer adsorption of N2 were similar to each other. The difference of threshold pressures is attributed to stabilized energies induced by interactions with graphene materials. Therefore, the layer number of graphene materials could be evaluated from the threshold pressures of adsorption, providing a guide to aid fabrication of graphene materials.