Fig. 4: Mechanical exfoliation to produce concentrated graphene dispersions.

a) Photographs of shear-exfoliated graphene dispersions (~60 mg mL−1) and Tyndall effect of dilute graphene dispersion. b The yield of graphene prepared under different conditions. c Adsorption amount and adsorption rate of Methyl blue (MB) from OG, BEG and concentrated graphene dispersions. d X-ray photoelectron spectroscopy (XPS) C 1 s spectrum and e Scanning electron microscope (SEM) image of freeze-dried graphene dispersions. f Atomic force microscope (AFM) image and g the thickness and size distribution of graphene nanosheets. h Transmission electron microscopy (TEM) image and i High-resolution TEM images (left) and selected-area electron diffraction images (right) of graphene nanosheets. The scale bars are 1 μm in e and f, 100 nm in h, and 5 nm in i (left) and 5 nm−1 in i (right).