Water vapor adsorption on low-temperature exfoliated graphene nanosheets

Adsorption of water vapor on graphene nanosheets (GNS) derived by vacuum-promoted low-temperature exfoliation method was investigated using a volumetric system. The pristine and thermally modified GNS were characterized with scanning electron microscopy (SEM) observation, Fourier transform infrared (FT-IR) analysis and nitrogen adsorption–desorption. The results show that the absorbed amount of water vapor against the pristine GNS can reach 249 cm3/g at 20 °C, and the capability of water vapor adsorption was weakened by heat treatment at 500 °C and 700 °C, the isosteric heat of water vapor adsorption against GNS is 42.6 kJ/mol based on the adsorption isotherms at 10 °C and 30 °C.

► The water vapor adsorption on graphene nanosheets (GNS) was investigated experimentally by volumetric system.
► GNSs exhibit a significant adsorption against water vapor, the water adsorbed amount of graphene can reach 249 cm3/g at 20 °C.
► The heat-treatment reduced the hydrophilic functional groups that resulted in the decrease of water vapor adsorption.
► The isosteric heat of water vapor adsorption against GNS is 42.6 kJ/mol, which is close to physical adsorption.