Few-layer graphene by assisted-exfoliation of graphite with layered silicate

Few-layer graphene has been achieved in liquid dispersion from graphite by the assistance of titanosilicate JDF-L1, using ultrasound and methanol as dispersive media. After a sedimentation step, both the dispersed and the sedimented phases were collected and then the titanosilicate was removed by alkaline hydrothermal dissolution from the mixed materials to obtain few-layer graphene (FLG) and sedimented material, respectively. The production of smaller particles was confirmed by means of N2 adsorption and zeta-potential measurements, so that the BET specific surface area increased from 20 m2/g of the raw graphite to 333 ± 22 m2/g in FLG. Raman spectroscopy shows a decrease in the ratio of intensities of the peaks G and 2D from 3.8 in the raw material to 2.5 in FLG. Particles as fine as 1.3 nm, corresponding to 4-layered FLG, were observed by AFM, while high-resolution TEM showed defect-free regions of graphene.