▎ 摘 要
Among four different biomass derived green and sustainable solvents namely levulinic acid (LA), ethyl lactate (EL), gamma-valerolactone (GVL) and formic acid (FA) only LA was found to exfoliate graphite to single and few layered graphene sheets. During exfoliation, the formation of LA crystals embedded with single layered graphene sheets was observed. The process is scalable and the solvent can be recovered and reused in five subsequent cycles of exfoliation for the large scale production of graphene sheets.